Fantastic Voyage

[A] It is mid-afternoon on the island of Bora Bora in French Polynesia. Thousands of cheering spectators crowd the shore to see the end of the Hawaiki Nui Va'a, a challenging 130-kilometer Polynesian canoe race that virtually stops the nation. "This is our heritage," says Manutea Owen, a former canoe champion and a hero on his home island of Huahine. "Our people came from over the sea by canoe. Sometimes when I'm out there competing, I try to imagine what they must have endured and the adventures they had crossing those huge distances."

Pioneers of the Pacific

[B] Manutea Owen's ancestors colonized nearly every island in the South Pacific. This was a remarkable feat1 of human navigation - comparable with humans going to the moon. Only recently have scientists begun to understand where these amazing voyagers came from, and how - with simple canoes and no navigation equipment - they reached hundreds of islands scattered across an ocean that covers nearly a third of the globe. This expansion into the Pacific was accomplished by two extraordinary civilizations: the Lapita and the Polynesians.

[C] From about 1300 to 800 B.C., the Lapita people colonized islands that stretch over millions of square kilometers, including the Solomon Islands, Vanuatu, Fiji, New Caledonia, and Samoa. Then, for unknown reasons, they stopped. There was an interval of around 1,000 years before the Polynesian civilization - descendants of the Lapita - launched a new period of exploration. They outdid the Lapita with unbelievable feats of navigation. They expanded the boundaries of their world until it was many times the size of that explored by their ancestors. Their colonies included the Cook Islands, French Polynesia, Hawaii, and Easter Island, eventually reaching South America around A.D. 1000.

How Did They Do It?

[D] There is one stubborn question for which archeology has yet to provide any answers. How did the Lapita and early Polynesian pioneers accomplish a feat that is analogous to a moon landing? Little evidence remains to help us understand their remarkable sailing skills. Unfortunately, no one has found an intact Lapita or early Polynesian canoe that might reveal the sailing techniques used. Nor do the oral histories2 and traditions of later Polynesians offer any insights as to how their ancestors navigated areas of open ocean thousands of kilometers wide without becoming lost. "All we can say for certain is that the Lapita had canoes that were capable of ocean voyages, and they had the ability to sail them," says Geoff Irwin, a professor of archeology at the University of Auckland. Nonetheless, scientists have some theories about the secrets of these explorers' successes.

[E] Sailors have always relied upon the so-called trade winds, winds that blow steadily and in predictable directions over the ocean's surface. Irwin notes that the Lapita's expansion into the Pacific was eastward, against steady trade winds. Sailing against the wind, he argues, may have been the key to their success: "They could sail out for days into the unknown …, secure in the knowledge that if they didn't find anything, they could turn around and catch a swift ride home on the trade winds." For returning explorers, successful or not, the geography of their own archipelagos3 provided a safety net. It ensured that sailors wouldn't sail too far and become lost in the open ocean. Vanuatu, for example, is a chain of islands 800 kilometers long with many islands within sight of each other. Once sailors hit that string of islands, they could find their way home.

[F] Irwin hypothesizes that once out in the open ocean, the explorers would detect a variety of clues to follow to land. This included seabirds and turtles that need islands on which to build their nests, coconuts and twigs4 carried out to sea, and the clouds that tend to form over some islands in the afternoon. It is also possible that Lapita sailors followed the smoke from distant volcanoes to new islands.

Helped by El Niño?

[G] These theories rely on one unproven point - that the Lapita and early Polynesians had mastered the skill of sailing against the wind using a technique called "tacking." Rather than give all the credit to their bravery and technique, Atholl Anderson of the Australian National University thinks that they might also have been lucky - helped by a weather phenomenon known as El Niño.

[H] El Niño occurs in the Pacific Ocean when the surface water temperature is unusually high. It disrupts world weather in a variety of ways. One of its effects is to cause trade winds in the South Pacific to weaken or to reverse direction and blow to the east. Scientists believe that El Niño phenomena were unusually frequent around the time of the Lapita expansion, and again between 1,200 and 1,600 years ago, when the early Polynesians began their even more distant voyages. Anderson believes that the Lapita may have taken advantage of trade winds blowing east instead of west, thereby voyaging far to the east without any knowledge of tacking techniques.

[I] The success of the Lapita and their descendants may have been due to their own sailing skills, to reverse trade winds, or to a mixture of both. Or it may even have been due to facts still unknown. But it is certain that by the time Europeans came to the Pacific, nearly every piece of land - hundreds of islands in all - had already been discovered by the Lapita and the Polynesians. Exactly why these ancient peoples set out on such giant migrations remains a mystery. However, as Professor Irwin puts it, "Whatever you believe, the really fascinating part of this story isn't the methods they used, but their motives. The Lapita, for example, didn't need to pick up and go; there was nothing forcing them, no overcrowded homeland. They went because they wanted to go and see what was over the horizon."

1 If you refer to something as a feat, you admire it because it is an impressive and difficult achievement.

2 Oral history is the collection and study of spoken memories, stories, and songs.

3 An archipelago is a large group or chain of islands.

4 A twig is a very small, thin branch.

In paragraph B, why does the author mention humans going to the moon?

Fantastic Voyage

[A] It is mid-afternoon on the island of Bora Bora in French Polynesia. Thousands of cheering spectators crowd the shore to see the end of the Hawaiki Nui Va'a, a challenging 130-kilometer Polynesian canoe race that virtually stops the nation. "This is our heritage," says Manutea Owen, a former canoe champion and a hero on his home island of Huahine. "Our people came from over the sea by canoe. Sometimes when I'm out there competing, I try to imagine what they must have endured and the adventures they had crossing those huge distances."

Pioneers of the Pacific

[B] Manutea Owen's ancestors colonized nearly every island in the South Pacific. This was a remarkable feat1 of human navigation - comparable with humans going to the moon. Only recently have scientists begun to understand where these amazing voyagers came from, and how - with simple canoes and no navigation equipment - they reached hundreds of islands scattered across an ocean that covers nearly a third of the globe. This expansion into the Pacific was accomplished by two extraordinary civilizations: the Lapita and the Polynesians.

[C] From about 1300 to 800 B.C., the Lapita people colonized islands that stretch over millions of square kilometers, including the Solomon Islands, Vanuatu, Fiji, New Caledonia, and Samoa. Then, for unknown reasons, they stopped. There was an interval of around 1,000 years before the Polynesian civilization - descendants of the Lapita - launched a new period of exploration. They outdid the Lapita with unbelievable feats of navigation. They expanded the boundaries of their world until it was many times the size of that explored by their ancestors. Their colonies included the Cook Islands, French Polynesia, Hawaii, and Easter Island, eventually reaching South America around A.D. 1000.

How Did They Do It?

[D] There is one stubborn question for which archeology has yet to provide any answers. How did the Lapita and early Polynesian pioneers accomplish a feat that is analogous to a moon landing? Little evidence remains to help us understand their remarkable sailing skills. Unfortunately, no one has found an intact Lapita or early Polynesian canoe that might reveal the sailing techniques used. Nor do the oral histories2 and traditions of later Polynesians offer any insights as to how their ancestors navigated areas of open ocean thousands of kilometers wide without becoming lost. "All we can say for certain is that the Lapita had canoes that were capable of ocean voyages, and they had the ability to sail them," says Geoff Irwin, a professor of archeology at the University of Auckland. Nonetheless, scientists have some theories about the secrets of these explorers' successes.

[E] Sailors have always relied upon the so-called trade winds, winds that blow steadily and in predictable directions over the ocean's surface. Irwin notes that the Lapita's expansion into the Pacific was eastward, against steady trade winds. Sailing against the wind, he argues, may have been the key to their success: "They could sail out for days into the unknown …, secure in the knowledge that if they didn't find anything, they could turn around and catch a swift ride home on the trade winds." For returning explorers, successful or not, the geography of their own archipelagos3 provided a safety net. It ensured that sailors wouldn't sail too far and become lost in the open ocean. Vanuatu, for example, is a chain of islands 800 kilometers long with many islands within sight of each other. Once sailors hit that string of islands, they could find their way home.

[F] Irwin hypothesizes that once out in the open ocean, the explorers would detect a variety of clues to follow to land. This included seabirds and turtles that need islands on which to build their nests, coconuts and twigs4 carried out to sea, and the clouds that tend to form over some islands in the afternoon. It is also possible that Lapita sailors followed the smoke from distant volcanoes to new islands.

Helped by El Niño?

[G] These theories rely on one unproven point - that the Lapita and early Polynesians had mastered the skill of sailing against the wind using a technique called "tacking." Rather than give all the credit to their bravery and technique, Atholl Anderson of the Australian National University thinks that they might also have been lucky - helped by a weather phenomenon known as El Niño.

[H] El Niño occurs in the Pacific Ocean when the surface water temperature is unusually high. It disrupts world weather in a variety of ways. One of its effects is to cause trade winds in the South Pacific to weaken or to reverse direction and blow to the east. Scientists believe that El Niño phenomena were unusually frequent around the time of the Lapita expansion, and again between 1,200 and 1,600 years ago, when the early Polynesians began their even more distant voyages. Anderson believes that the Lapita may have taken advantage of trade winds blowing east instead of west, thereby voyaging far to the east without any knowledge of tacking techniques.

[I] The success of the Lapita and their descendants may have been due to their own sailing skills, to reverse trade winds, or to a mixture of both. Or it may even have been due to facts still unknown. But it is certain that by the time Europeans came to the Pacific, nearly every piece of land - hundreds of islands in all - had already been discovered by the Lapita and the Polynesians. Exactly why these ancient peoples set out on such giant migrations remains a mystery. However, as Professor Irwin puts it, "Whatever you believe, the really fascinating part of this story isn't the methods they used, but their motives. The Lapita, for example, didn't need to pick up and go; there was nothing forcing them, no overcrowded homeland. They went because they wanted to go and see what was over the horizon."

1 If you refer to something as a feat, you admire it because it is an impressive and difficult achievement.

2 Oral history is the collection and study of spoken memories, stories, and songs.

3 An archipelago is a large group or chain of islands.

4 A twig is a very small, thin branch.

According to Irwin, how could early explorers have relied on trade winds?

Fantastic Voyage

[A] It is mid-afternoon on the island of Bora Bora in French Polynesia. Thousands of cheering spectators crowd the shore to see the end of the Hawaiki Nui Va'a, a challenging 130-kilometer Polynesian canoe race that virtually stops the nation. "This is our heritage," says Manutea Owen, a former canoe champion and a hero on his home island of Huahine. "Our people came from over the sea by canoe. Sometimes when I'm out there competing, I try to imagine what they must have endured and the adventures they had crossing those huge distances."

Pioneers of the Pacific

[B] Manutea Owen's ancestors colonized nearly every island in the South Pacific. This was a remarkable feat1 of human navigation - comparable with humans going to the moon. Only recently have scientists begun to understand where these amazing voyagers came from, and how - with simple canoes and no navigation equipment - they reached hundreds of islands scattered across an ocean that covers nearly a third of the globe. This expansion into the Pacific was accomplished by two extraordinary civilizations: the Lapita and the Polynesians.

[C] From about 1300 to 800 B.C., the Lapita people colonized islands that stretch over millions of square kilometers, including the Solomon Islands, Vanuatu, Fiji, New Caledonia, and Samoa. Then, for unknown reasons, they stopped. There was an interval of around 1,000 years before the Polynesian civilization - descendants of the Lapita - launched a new period of exploration. They outdid the Lapita with unbelievable feats of navigation. They expanded the boundaries of their world until it was many times the size of that explored by their ancestors. Their colonies included the Cook Islands, French Polynesia, Hawaii, and Easter Island, eventually reaching South America around A.D. 1000.

How Did They Do It?

[D] There is one stubborn question for which archeology has yet to provide any answers. How did the Lapita and early Polynesian pioneers accomplish a feat that is analogous to a moon landing? Little evidence remains to help us understand their remarkable sailing skills. Unfortunately, no one has found an intact Lapita or early Polynesian canoe that might reveal the sailing techniques used. Nor do the oral histories2 and traditions of later Polynesians offer any insights as to how their ancestors navigated areas of open ocean thousands of kilometers wide without becoming lost. "All we can say for certain is that the Lapita had canoes that were capable of ocean voyages, and they had the ability to sail them," says Geoff Irwin, a professor of archeology at the University of Auckland. Nonetheless, scientists have some theories about the secrets of these explorers' successes.

[E] Sailors have always relied upon the so-called trade winds, winds that blow steadily and in predictable directions over the ocean's surface. Irwin notes that the Lapita's expansion into the Pacific was eastward, against steady trade winds. Sailing against the wind, he argues, may have been the key to their success: "They could sail out for days into the unknown …, secure in the knowledge that if they didn't find anything, they could turn around and catch a swift ride home on the trade winds." For returning explorers, successful or not, the geography of their own archipelagos3 provided a safety net. It ensured that sailors wouldn't sail too far and become lost in the open ocean. Vanuatu, for example, is a chain of islands 800 kilometers long with many islands within sight of each other. Once sailors hit that string of islands, they could find their way home.

[F] Irwin hypothesizes that once out in the open ocean, the explorers would detect a variety of clues to follow to land. This included seabirds and turtles that need islands on which to build their nests, coconuts and twigs4 carried out to sea, and the clouds that tend to form over some islands in the afternoon. It is also possible that Lapita sailors followed the smoke from distant volcanoes to new islands.

Helped by El Niño?

[G] These theories rely on one unproven point - that the Lapita and early Polynesians had mastered the skill of sailing against the wind using a technique called "tacking." Rather than give all the credit to their bravery and technique, Atholl Anderson of the Australian National University thinks that they might also have been lucky - helped by a weather phenomenon known as El Niño.

[H] El Niño occurs in the Pacific Ocean when the surface water temperature is unusually high. It disrupts world weather in a variety of ways. One of its effects is to cause trade winds in the South Pacific to weaken or to reverse direction and blow to the east. Scientists believe that El Niño phenomena were unusually frequent around the time of the Lapita expansion, and again between 1,200 and 1,600 years ago, when the early Polynesians began their even more distant voyages. Anderson believes that the Lapita may have taken advantage of trade winds blowing east instead of west, thereby voyaging far to the east without any knowledge of tacking techniques.

[I] The success of the Lapita and their descendants may have been due to their own sailing skills, to reverse trade winds, or to a mixture of both. Or it may even have been due to facts still unknown. But it is certain that by the time Europeans came to the Pacific, nearly every piece of land - hundreds of islands in all - had already been discovered by the Lapita and the Polynesians. Exactly why these ancient peoples set out on such giant migrations remains a mystery. However, as Professor Irwin puts it, "Whatever you believe, the really fascinating part of this story isn't the methods they used, but their motives. The Lapita, for example, didn't need to pick up and go; there was nothing forcing them, no overcrowded homeland. They went because they wanted to go and see what was over the horizon."

1 If you refer to something as a feat, you admire it because it is an impressive and difficult achievement.

2 Oral history is the collection and study of spoken memories, stories, and songs.

3 An archipelago is a large group or chain of islands.

4 A twig is a very small, thin branch.

Which of the following is NOT mentioned as a clue that sailors might have used to get to land?

Fantastic Voyage

[A] It is mid-afternoon on the island of Bora Bora in French Polynesia. Thousands of cheering spectators crowd the shore to see the end of the Hawaiki Nui Va'a, a challenging 130-kilometer Polynesian canoe race that virtually stops the nation. "This is our heritage," says Manutea Owen, a former canoe champion and a hero on his home island of Huahine. "Our people came from over the sea by canoe. Sometimes when I'm out there competing, I try to imagine what they must have endured and the adventures they had crossing those huge distances."

Pioneers of the Pacific

[B] Manutea Owen's ancestors colonized nearly every island in the South Pacific. This was a remarkable feat1 of human navigation - comparable with humans going to the moon. Only recently have scientists begun to understand where these amazing voyagers came from, and how - with simple canoes and no navigation equipment - they reached hundreds of islands scattered across an ocean that covers nearly a third of the globe. This expansion into the Pacific was accomplished by two extraordinary civilizations: the Lapita and the Polynesians.

[C] From about 1300 to 800 B.C., the Lapita people colonized islands that stretch over millions of square kilometers, including the Solomon Islands, Vanuatu, Fiji, New Caledonia, and Samoa. Then, for unknown reasons, they stopped. There was an interval of around 1,000 years before the Polynesian civilization - descendants of the Lapita - launched a new period of exploration. They outdid the Lapita with unbelievable feats of navigation. They expanded the boundaries of their world until it was many times the size of that explored by their ancestors. Their colonies included the Cook Islands, French Polynesia, Hawaii, and Easter Island, eventually reaching South America around A.D. 1000.

How Did They Do It?

[D] There is one stubborn question for which archeology has yet to provide any answers. How did the Lapita and early Polynesian pioneers accomplish a feat that is analogous to a moon landing? Little evidence remains to help us understand their remarkable sailing skills. Unfortunately, no one has found an intact Lapita or early Polynesian canoe that might reveal the sailing techniques used. Nor do the oral histories2 and traditions of later Polynesians offer any insights as to how their ancestors navigated areas of open ocean thousands of kilometers wide without becoming lost. "All we can say for certain is that the Lapita had canoes that were capable of ocean voyages, and they had the ability to sail them," says Geoff Irwin, a professor of archeology at the University of Auckland. Nonetheless, scientists have some theories about the secrets of these explorers' successes.

[E] Sailors have always relied upon the so-called trade winds, winds that blow steadily and in predictable directions over the ocean's surface. Irwin notes that the Lapita's expansion into the Pacific was eastward, against steady trade winds. Sailing against the wind, he argues, may have been the key to their success: "They could sail out for days into the unknown …, secure in the knowledge that if they didn't find anything, they could turn around and catch a swift ride home on the trade winds." For returning explorers, successful or not, the geography of their own archipelagos3 provided a safety net. It ensured that sailors wouldn't sail too far and become lost in the open ocean. Vanuatu, for example, is a chain of islands 800 kilometers long with many islands within sight of each other. Once sailors hit that string of islands, they could find their way home.

[F] Irwin hypothesizes that once out in the open ocean, the explorers would detect a variety of clues to follow to land. This included seabirds and turtles that need islands on which to build their nests, coconuts and twigs4 carried out to sea, and the clouds that tend to form over some islands in the afternoon. It is also possible that Lapita sailors followed the smoke from distant volcanoes to new islands.

Helped by El Niño?

[G] These theories rely on one unproven point - that the Lapita and early Polynesians had mastered the skill of sailing against the wind using a technique called "tacking." Rather than give all the credit to their bravery and technique, Atholl Anderson of the Australian National University thinks that they might also have been lucky - helped by a weather phenomenon known as El Niño.

[H] El Niño occurs in the Pacific Ocean when the surface water temperature is unusually high. It disrupts world weather in a variety of ways. One of its effects is to cause trade winds in the South Pacific to weaken or to reverse direction and blow to the east. Scientists believe that El Niño phenomena were unusually frequent around the time of the Lapita expansion, and again between 1,200 and 1,600 years ago, when the early Polynesians began their even more distant voyages. Anderson believes that the Lapita may have taken advantage of trade winds blowing east instead of west, thereby voyaging far to the east without any knowledge of tacking techniques.

[I] The success of the Lapita and their descendants may have been due to their own sailing skills, to reverse trade winds, or to a mixture of both. Or it may even have been due to facts still unknown. But it is certain that by the time Europeans came to the Pacific, nearly every piece of land - hundreds of islands in all - had already been discovered by the Lapita and the Polynesians. Exactly why these ancient peoples set out on such giant migrations remains a mystery. However, as Professor Irwin puts it, "Whatever you believe, the really fascinating part of this story isn't the methods they used, but their motives. The Lapita, for example, didn't need to pick up and go; there was nothing forcing them, no overcrowded homeland. They went because they wanted to go and see what was over the horizon."

1 If you refer to something as a feat, you admire it because it is an impressive and difficult achievement.

2 Oral history is the collection and study of spoken memories, stories, and songs.

3 An archipelago is a large group or chain of islands.

4 A twig is a very small, thin branch.

What does the word motives in paragraph I mean?

Fantastic Voyage

[A] It is mid-afternoon on the island of Bora Bora in French Polynesia. Thousands of cheering spectators crowd the shore to see the end of the Hawaiki Nui Va'a, a challenging 130-kilometer Polynesian canoe race that virtually stops the nation. "This is our heritage," says Manutea Owen, a former canoe champion and a hero on his home island of Huahine. "Our people came from over the sea by canoe. Sometimes when I'm out there competing, I try to imagine what they must have endured and the adventures they had crossing those huge distances."

Pioneers of the Pacific

[B] Manutea Owen's ancestors colonized nearly every island in the South Pacific. This was a remarkable feat1 of human navigation - comparable with humans going to the moon. Only recently have scientists begun to understand where these amazing voyagers came from, and how - with simple canoes and no navigation equipment - they reached hundreds of islands scattered across an ocean that covers nearly a third of the globe. This expansion into the Pacific was accomplished by two extraordinary civilizations: the Lapita and the Polynesians.

[C] From about 1300 to 800 B.C., the Lapita people colonized islands that stretch over millions of square kilometers, including the Solomon Islands, Vanuatu, Fiji, New Caledonia, and Samoa. Then, for unknown reasons, they stopped. There was an interval of around 1,000 years before the Polynesian civilization - descendants of the Lapita - launched a new period of exploration. They outdid the Lapita with unbelievable feats of navigation. They expanded the boundaries of their world until it was many times the size of that explored by their ancestors. Their colonies included the Cook Islands, French Polynesia, Hawaii, and Easter Island, eventually reaching South America around A.D. 1000.

How Did They Do It?

[D] There is one stubborn question for which archeology has yet to provide any answers. How did the Lapita and early Polynesian pioneers accomplish a feat that is analogous to a moon landing? Little evidence remains to help us understand their remarkable sailing skills. Unfortunately, no one has found an intact Lapita or early Polynesian canoe that might reveal the sailing techniques used. Nor do the oral histories2 and traditions of later Polynesians offer any insights as to how their ancestors navigated areas of open ocean thousands of kilometers wide without becoming lost. "All we can say for certain is that the Lapita had canoes that were capable of ocean voyages, and they had the ability to sail them," says Geoff Irwin, a professor of archeology at the University of Auckland. Nonetheless, scientists have some theories about the secrets of these explorers' successes.

[E] Sailors have always relied upon the so-called trade winds, winds that blow steadily and in predictable directions over the ocean's surface. Irwin notes that the Lapita's expansion into the Pacific was eastward, against steady trade winds. Sailing against the wind, he argues, may have been the key to their success: "They could sail out for days into the unknown …, secure in the knowledge that if they didn't find anything, they could turn around and catch a swift ride home on the trade winds." For returning explorers, successful or not, the geography of their own archipelagos3 provided a safety net. It ensured that sailors wouldn't sail too far and become lost in the open ocean. Vanuatu, for example, is a chain of islands 800 kilometers long with many islands within sight of each other. Once sailors hit that string of islands, they could find their way home.

[F] Irwin hypothesizes that once out in the open ocean, the explorers would detect a variety of clues to follow to land. This included seabirds and turtles that need islands on which to build their nests, coconuts and twigs4 carried out to sea, and the clouds that tend to form over some islands in the afternoon. It is also possible that Lapita sailors followed the smoke from distant volcanoes to new islands.

Helped by El Niño?

[G] These theories rely on one unproven point - that the Lapita and early Polynesians had mastered the skill of sailing against the wind using a technique called "tacking." Rather than give all the credit to their bravery and technique, Atholl Anderson of the Australian National University thinks that they might also have been lucky - helped by a weather phenomenon known as El Niño.

[H] El Niño occurs in the Pacific Ocean when the surface water temperature is unusually high. It disrupts world weather in a variety of ways. One of its effects is to cause trade winds in the South Pacific to weaken or to reverse direction and blow to the east. Scientists believe that El Niño phenomena were unusually frequent around the time of the Lapita expansion, and again between 1,200 and 1,600 years ago, when the early Polynesians began their even more distant voyages. Anderson believes that the Lapita may have taken advantage of trade winds blowing east instead of west, thereby voyaging far to the east without any knowledge of tacking techniques.

[I] The success of the Lapita and their descendants may have been due to their own sailing skills, to reverse trade winds, or to a mixture of both. Or it may even have been due to facts still unknown. But it is certain that by the time Europeans came to the Pacific, nearly every piece of land - hundreds of islands in all - had already been discovered by the Lapita and the Polynesians. Exactly why these ancient peoples set out on such giant migrations remains a mystery. However, as Professor Irwin puts it, "Whatever you believe, the really fascinating part of this story isn't the methods they used, but their motives. The Lapita, for example, didn't need to pick up and go; there was nothing forcing them, no overcrowded homeland. They went because they wanted to go and see what was over the horizon."

1 If you refer to something as a feat, you admire it because it is an impressive and difficult achievement.

2 Oral history is the collection and study of spoken memories, stories, and songs.

3 An archipelago is a large group or chain of islands.

4 A twig is a very small, thin branch.

When does El Niño occur in the Pacific Ocean?

Fantastic Voyage

[A] It is mid-afternoon on the island of Bora Bora in French Polynesia. Thousands of cheering spectators crowd the shore to see the end of the Hawaiki Nui Va'a, a challenging 130-kilometer Polynesian canoe race that virtually stops the nation. "This is our heritage," says Manutea Owen, a former canoe champion and a hero on his home island of Huahine. "Our people came from over the sea by canoe. Sometimes when I'm out there competing, I try to imagine what they must have endured and the adventures they had crossing those huge distances."

Pioneers of the Pacific

[B] Manutea Owen's ancestors colonized nearly every island in the South Pacific. This was a remarkable feat1 of human navigation - comparable with humans going to the moon. Only recently have scientists begun to understand where these amazing voyagers came from, and how - with simple canoes and no navigation equipment - they reached hundreds of islands scattered across an ocean that covers nearly a third of the globe. This expansion into the Pacific was accomplished by two extraordinary civilizations: the Lapita and the Polynesians.

[C] From about 1300 to 800 B.C., the Lapita people colonized islands that stretch over millions of square kilometers, including the Solomon Islands, Vanuatu, Fiji, New Caledonia, and Samoa. Then, for unknown reasons, they stopped. There was an interval of around 1,000 years before the Polynesian civilization - descendants of the Lapita - launched a new period of exploration. They outdid the Lapita with unbelievable feats of navigation. They expanded the boundaries of their world until it was many times the size of that explored by their ancestors. Their colonies included the Cook Islands, French Polynesia, Hawaii, and Easter Island, eventually reaching South America around A.D. 1000.

How Did They Do It?

[D] There is one stubborn question for which archeology has yet to provide any answers. How did the Lapita and early Polynesian pioneers accomplish a feat that is analogous to a moon landing? Little evidence remains to help us understand their remarkable sailing skills. Unfortunately, no one has found an intact Lapita or early Polynesian canoe that might reveal the sailing techniques used. Nor do the oral histories2 and traditions of later Polynesians offer any insights as to how their ancestors navigated areas of open ocean thousands of kilometers wide without becoming lost. "All we can say for certain is that the Lapita had canoes that were capable of ocean voyages, and they had the ability to sail them," says Geoff Irwin, a professor of archeology at the University of Auckland. Nonetheless, scientists have some theories about the secrets of these explorers' successes.

[E] Sailors have always relied upon the so-called trade winds, winds that blow steadily and in predictable directions over the ocean's surface. Irwin notes that the Lapita's expansion into the Pacific was eastward, against steady trade winds. Sailing against the wind, he argues, may have been the key to their success: "They could sail out for days into the unknown …, secure in the knowledge that if they didn't find anything, they could turn around and catch a swift ride home on the trade winds." For returning explorers, successful or not, the geography of their own archipelagos3 provided a safety net. It ensured that sailors wouldn't sail too far and become lost in the open ocean. Vanuatu, for example, is a chain of islands 800 kilometers long with many islands within sight of each other. Once sailors hit that string of islands, they could find their way home.

[F] Irwin hypothesizes that once out in the open ocean, the explorers would detect a variety of clues to follow to land. This included seabirds and turtles that need islands on which to build their nests, coconuts and twigs4 carried out to sea, and the clouds that tend to form over some islands in the afternoon. It is also possible that Lapita sailors followed the smoke from distant volcanoes to new islands.

Helped by El Niño?

[G] These theories rely on one unproven point - that the Lapita and early Polynesians had mastered the skill of sailing against the wind using a technique called "tacking." Rather than give all the credit to their bravery and technique, Atholl Anderson of the Australian National University thinks that they might also have been lucky - helped by a weather phenomenon known as El Niño.

[H] El Niño occurs in the Pacific Ocean when the surface water temperature is unusually high. It disrupts world weather in a variety of ways. One of its effects is to cause trade winds in the South Pacific to weaken or to reverse direction and blow to the east. Scientists believe that El Niño phenomena were unusually frequent around the time of the Lapita expansion, and again between 1,200 and 1,600 years ago, when the early Polynesians began their even more distant voyages. Anderson believes that the Lapita may have taken advantage of trade winds blowing east instead of west, thereby voyaging far to the east without any knowledge of tacking techniques.

[I] The success of the Lapita and their descendants may have been due to their own sailing skills, to reverse trade winds, or to a mixture of both. Or it may even have been due to facts still unknown. But it is certain that by the time Europeans came to the Pacific, nearly every piece of land - hundreds of islands in all - had already been discovered by the Lapita and the Polynesians. Exactly why these ancient peoples set out on such giant migrations remains a mystery. However, as Professor Irwin puts it, "Whatever you believe, the really fascinating part of this story isn't the methods they used, but their motives. The Lapita, for example, didn't need to pick up and go; there was nothing forcing them, no overcrowded homeland. They went because they wanted to go and see what was over the horizon."

1 If you refer to something as a feat, you admire it because it is an impressive and difficult achievement.

2 Oral history is the collection and study of spoken memories, stories, and songs.

3 An archipelago is a large group or chain of islands.

4 A twig is a very small, thin branch.

Is the following sentence fact or speculation?

From about 1300 to 800 B.C., the Lapita people colonized islands that stretch over millions of square kilometers, including the Solomon Islands, Vanuatu, Fiji, New Caledonia, and Samoa.

Fantastic Voyage

[A] It is mid-afternoon on the island of Bora Bora in French Polynesia. Thousands of cheering spectators crowd the shore to see the end of the Hawaiki Nui Va'a, a challenging 130-kilometer Polynesian canoe race that virtually stops the nation. "This is our heritage," says Manutea Owen, a former canoe champion and a hero on his home island of Huahine. "Our people came from over the sea by canoe. Sometimes when I'm out there competing, I try to imagine what they must have endured and the adventures they had crossing those huge distances."

Pioneers of the Pacific

[B] Manutea Owen's ancestors colonized nearly every island in the South Pacific. This was a remarkable feat1 of human navigation - comparable with humans going to the moon. Only recently have scientists begun to understand where these amazing voyagers came from, and how - with simple canoes and no navigation equipment - they reached hundreds of islands scattered across an ocean that covers nearly a third of the globe. This expansion into the Pacific was accomplished by two extraordinary civilizations: the Lapita and the Polynesians.

[C] From about 1300 to 800 B.C., the Lapita people colonized islands that stretch over millions of square kilometers, including the Solomon Islands, Vanuatu, Fiji, New Caledonia, and Samoa. Then, for unknown reasons, they stopped. There was an interval of around 1,000 years before the Polynesian civilization - descendants of the Lapita - launched a new period of exploration. They outdid the Lapita with unbelievable feats of navigation. They expanded the boundaries of their world until it was many times the size of that explored by their ancestors. Their colonies included the Cook Islands, French Polynesia, Hawaii, and Easter Island, eventually reaching South America around A.D. 1000.

How Did They Do It?

[D] There is one stubborn question for which archeology has yet to provide any answers. How did the Lapita and early Polynesian pioneers accomplish a feat that is analogous to a moon landing? Little evidence remains to help us understand their remarkable sailing skills. Unfortunately, no one has found an intact Lapita or early Polynesian canoe that might reveal the sailing techniques used. Nor do the oral histories2 and traditions of later Polynesians offer any insights as to how their ancestors navigated areas of open ocean thousands of kilometers wide without becoming lost. "All we can say for certain is that the Lapita had canoes that were capable of ocean voyages, and they had the ability to sail them," says Geoff Irwin, a professor of archeology at the University of Auckland. Nonetheless, scientists have some theories about the secrets of these explorers' successes.

[E] Sailors have always relied upon the so-called trade winds, winds that blow steadily and in predictable directions over the ocean's surface. Irwin notes that the Lapita's expansion into the Pacific was eastward, against steady trade winds. Sailing against the wind, he argues, may have been the key to their success: "They could sail out for days into the unknown …, secure in the knowledge that if they didn't find anything, they could turn around and catch a swift ride home on the trade winds." For returning explorers, successful or not, the geography of their own archipelagos3 provided a safety net. It ensured that sailors wouldn't sail too far and become lost in the open ocean. Vanuatu, for example, is a chain of islands 800 kilometers long with many islands within sight of each other. Once sailors hit that string of islands, they could find their way home.

[F] Irwin hypothesizes that once out in the open ocean, the explorers would detect a variety of clues to follow to land. This included seabirds and turtles that need islands on which to build their nests, coconuts and twigs4 carried out to sea, and the clouds that tend to form over some islands in the afternoon. It is also possible that Lapita sailors followed the smoke from distant volcanoes to new islands.

Helped by El Niño?

[G] These theories rely on one unproven point - that the Lapita and early Polynesians had mastered the skill of sailing against the wind using a technique called "tacking." Rather than give all the credit to their bravery and technique, Atholl Anderson of the Australian National University thinks that they might also have been lucky - helped by a weather phenomenon known as El Niño.

[H] El Niño occurs in the Pacific Ocean when the surface water temperature is unusually high. It disrupts world weather in a variety of ways. One of its effects is to cause trade winds in the South Pacific to weaken or to reverse direction and blow to the east. Scientists believe that El Niño phenomena were unusually frequent around the time of the Lapita expansion, and again between 1,200 and 1,600 years ago, when the early Polynesians began their even more distant voyages. Anderson believes that the Lapita may have taken advantage of trade winds blowing east instead of west, thereby voyaging far to the east without any knowledge of tacking techniques.

[I] The success of the Lapita and their descendants may have been due to their own sailing skills, to reverse trade winds, or to a mixture of both. Or it may even have been due to facts still unknown. But it is certain that by the time Europeans came to the Pacific, nearly every piece of land - hundreds of islands in all - had already been discovered by the Lapita and the Polynesians. Exactly why these ancient peoples set out on such giant migrations remains a mystery. However, as Professor Irwin puts it, "Whatever you believe, the really fascinating part of this story isn't the methods they used, but their motives. The Lapita, for example, didn't need to pick up and go; there was nothing forcing them, no overcrowded homeland. They went because they wanted to go and see what was over the horizon."

1 If you refer to something as a feat, you admire it because it is an impressive and difficult achievement.

2 Oral history is the collection and study of spoken memories, stories, and songs.

3 An archipelago is a large group or chain of islands.

4 A twig is a very small, thin branch.

Is the following sentence fact or speculation?

Vanuatu, for example, is a chain of islands 800 kilometers long with many islands within sight of each

other.

Fantastic Voyage

[A] It is mid-afternoon on the island of Bora Bora in French Polynesia. Thousands of cheering spectators crowd the shore to see the end of the Hawaiki Nui Va'a, a challenging 130-kilometer Polynesian canoe race that virtually stops the nation. "This is our heritage," says Manutea Owen, a former canoe champion and a hero on his home island of Huahine. "Our people came from over the sea by canoe. Sometimes when I'm out there competing, I try to imagine what they must have endured and the adventures they had crossing those huge distances."

Pioneers of the Pacific

[B] Manutea Owen's ancestors colonized nearly every island in the South Pacific. This was a remarkable feat1 of human navigation - comparable with humans going to the moon. Only recently have scientists begun to understand where these amazing voyagers came from, and how - with simple canoes and no navigation equipment - they reached hundreds of islands scattered across an ocean that covers nearly a third of the globe. This expansion into the Pacific was accomplished by two extraordinary civilizations: the Lapita and the Polynesians.

[C] From about 1300 to 800 B.C., the Lapita people colonized islands that stretch over millions of square kilometers, including the Solomon Islands, Vanuatu, Fiji, New Caledonia, and Samoa. Then, for unknown reasons, they stopped. There was an interval of around 1,000 years before the Polynesian civilization - descendants of the Lapita - launched a new period of exploration. They outdid the Lapita with unbelievable feats of navigation. They expanded the boundaries of their world until it was many times the size of that explored by their ancestors. Their colonies included the Cook Islands, French Polynesia, Hawaii, and Easter Island, eventually reaching South America around A.D. 1000.

How Did They Do It?

[D] There is one stubborn question for which archeology has yet to provide any answers. How did the Lapita and early Polynesian pioneers accomplish a feat that is analogous to a moon landing? Little evidence remains to help us understand their remarkable sailing skills. Unfortunately, no one has found an intact Lapita or early Polynesian canoe that might reveal the sailing techniques used. Nor do the oral histories2 and traditions of later Polynesians offer any insights as to how their ancestors navigated areas of open ocean thousands of kilometers wide without becoming lost. "All we can say for certain is that the Lapita had canoes that were capable of ocean voyages, and they had the ability to sail them," says Geoff Irwin, a professor of archeology at the University of Auckland. Nonetheless, scientists have some theories about the secrets of these explorers' successes.

[E] Sailors have always relied upon the so-called trade winds, winds that blow steadily and in predictable directions over the ocean's surface. Irwin notes that the Lapita's expansion into the Pacific was eastward, against steady trade winds. Sailing against the wind, he argues, may have been the key to their success: "They could sail out for days into the unknown …, secure in the knowledge that if they didn't find anything, they could turn around and catch a swift ride home on the trade winds." For returning explorers, successful or not, the geography of their own archipelagos3 provided a safety net. It ensured that sailors wouldn't sail too far and become lost in the open ocean. Vanuatu, for example, is a chain of islands 800 kilometers long with many islands within sight of each other. Once sailors hit that string of islands, they could find their way home.

[F] Irwin hypothesizes that once out in the open ocean, the explorers would detect a variety of clues to follow to land. This included seabirds and turtles that need islands on which to build their nests, coconuts and twigs4 carried out to sea, and the clouds that tend to form over some islands in the afternoon. It is also possible that Lapita sailors followed the smoke from distant volcanoes to new islands.

Helped by El Niño?

[G] These theories rely on one unproven point - that the Lapita and early Polynesians had mastered the skill of sailing against the wind using a technique called "tacking." Rather than give all the credit to their bravery and technique, Atholl Anderson of the Australian National University thinks that they might also have been lucky - helped by a weather phenomenon known as El Niño.

[H] El Niño occurs in the Pacific Ocean when the surface water temperature is unusually high. It disrupts world weather in a variety of ways. One of its effects is to cause trade winds in the South Pacific to weaken or to reverse direction and blow to the east. Scientists believe that El Niño phenomena were unusually frequent around the time of the Lapita expansion, and again between 1,200 and 1,600 years ago, when the early Polynesians began their even more distant voyages. Anderson believes that the Lapita may have taken advantage of trade winds blowing east instead of west, thereby voyaging far to the east without any knowledge of tacking techniques.

[I] The success of the Lapita and their descendants may have been due to their own sailing skills, to reverse trade winds, or to a mixture of both. Or it may even have been due to facts still unknown. But it is certain that by the time Europeans came to the Pacific, nearly every piece of land - hundreds of islands in all - had already been discovered by the Lapita and the Polynesians. Exactly why these ancient peoples set out on such giant migrations remains a mystery. However, as Professor Irwin puts it, "Whatever you believe, the really fascinating part of this story isn't the methods they used, but their motives. The Lapita, for example, didn't need to pick up and go; there was nothing forcing them, no overcrowded homeland. They went because they wanted to go and see what was over the horizon."

1 If you refer to something as a feat, you admire it because it is an impressive and difficult achievement.

2 Oral history is the collection and study of spoken memories, stories, and songs.

3 An archipelago is a large group or chain of islands.

4 A twig is a very small, thin branch.

Is the following sentence fact or speculation?

Scientists believe that El Niño phenomena were unusually frequent around the time of the Lapita expansion, and again between 1,200 and 1,600 years ago, when the early Polynesians began their even more distant voyages.

Fantastic Voyage

[A] It is mid-afternoon on the island of Bora Bora in French Polynesia. Thousands of cheering spectators crowd the shore to see the end of the Hawaiki Nui Va'a, a challenging 130-kilometer Polynesian canoe race that virtually stops the nation. "This is our heritage," says Manutea Owen, a former canoe champion and a hero on his home island of Huahine. "Our people came from over the sea by canoe. Sometimes when I'm out there competing, I try to imagine what they must have endured and the adventures they had crossing those huge distances."

Pioneers of the Pacific

[B] Manutea Owen's ancestors colonized nearly every island in the South Pacific. This was a remarkable feat1 of human navigation - comparable with humans going to the moon. Only recently have scientists begun to understand where these amazing voyagers came from, and how - with simple canoes and no navigation equipment - they reached hundreds of islands scattered across an ocean that covers nearly a third of the globe. This expansion into the Pacific was accomplished by two extraordinary civilizations: the Lapita and the Polynesians.

[C] From about 1300 to 800 B.C., the Lapita people colonized islands that stretch over millions of square kilometers, including the Solomon Islands, Vanuatu, Fiji, New Caledonia, and Samoa. Then, for unknown reasons, they stopped. There was an interval of around 1,000 years before the Polynesian civilization - descendants of the Lapita - launched a new period of exploration. They outdid the Lapita with unbelievable feats of navigation. They expanded the boundaries of their world until it was many times the size of that explored by their ancestors. Their colonies included the Cook Islands, French Polynesia, Hawaii, and Easter Island, eventually reaching South America around A.D. 1000.

How Did They Do It?

[D] There is one stubborn question for which archeology has yet to provide any answers. How did the Lapita and early Polynesian pioneers accomplish a feat that is analogous to a moon landing? Little evidence remains to help us understand their remarkable sailing skills. Unfortunately, no one has found an intact Lapita or early Polynesian canoe that might reveal the sailing techniques used. Nor do the oral histories2 and traditions of later Polynesians offer any insights as to how their ancestors navigated areas of open ocean thousands of kilometers wide without becoming lost. "All we can say for certain is that the Lapita had canoes that were capable of ocean voyages, and they had the ability to sail them," says Geoff Irwin, a professor of archeology at the University of Auckland. Nonetheless, scientists have some theories about the secrets of these explorers' successes.

[E] Sailors have always relied upon the so-called trade winds, winds that blow steadily and in predictable directions over the ocean's surface. Irwin notes that the Lapita's expansion into the Pacific was eastward, against steady trade winds. Sailing against the wind, he argues, may have been the key to their success: "They could sail out for days into the unknown …, secure in the knowledge that if they didn't find anything, they could turn around and catch a swift ride home on the trade winds." For returning explorers, successful or not, the geography of their own archipelagos3 provided a safety net. It ensured that sailors wouldn't sail too far and become lost in the open ocean. Vanuatu, for example, is a chain of islands 800 kilometers long with many islands within sight of each other. Once sailors hit that string of islands, they could find their way home.

[F] Irwin hypothesizes that once out in the open ocean, the explorers would detect a variety of clues to follow to land. This included seabirds and turtles that need islands on which to build their nests, coconuts and twigs4 carried out to sea, and the clouds that tend to form over some islands in the afternoon. It is also possible that Lapita sailors followed the smoke from distant volcanoes to new islands.

Helped by El Niño?

[G] These theories rely on one unproven point - that the Lapita and early Polynesians had mastered the skill of sailing against the wind using a technique called "tacking." Rather than give all the credit to their bravery and technique, Atholl Anderson of the Australian National University thinks that they might also have been lucky - helped by a weather phenomenon known as El Niño.

[H] El Niño occurs in the Pacific Ocean when the surface water temperature is unusually high. It disrupts world weather in a variety of ways. One of its effects is to cause trade winds in the South Pacific to weaken or to reverse direction and blow to the east. Scientists believe that El Niño phenomena were unusually frequent around the time of the Lapita expansion, and again between 1,200 and 1,600 years ago, when the early Polynesians began their even more distant voyages. Anderson believes that the Lapita may have taken advantage of trade winds blowing east instead of west, thereby voyaging far to the east without any knowledge of tacking techniques.

[I] The success of the Lapita and their descendants may have been due to their own sailing skills, to reverse trade winds, or to a mixture of both. Or it may even have been due to facts still unknown. But it is certain that by the time Europeans came to the Pacific, nearly every piece of land - hundreds of islands in all - had already been discovered by the Lapita and the Polynesians. Exactly why these ancient peoples set out on such giant migrations remains a mystery. However, as Professor Irwin puts it, "Whatever you believe, the really fascinating part of this story isn't the methods they used, but their motives. The Lapita, for example, didn't need to pick up and go; there was nothing forcing them, no overcrowded homeland. They went because they wanted to go and see what was over the horizon."

1 If you refer to something as a feat, you admire it because it is an impressive and difficult achievement.

2 Oral history is the collection and study of spoken memories, stories, and songs.

3 An archipelago is a large group or chain of islands.

4 A twig is a very small, thin branch.

Is the following sentence fact or speculation?

The success of the Lapita and their descendants may have been due to their own sailing skills, to reverse trade winds, or to a mixture of both.

Restless1 Genes

[A] The drive to see what lies beyond that far horizon or that ocean - or this planet - is a defining part of human identity and success. Not all of us ache to ride a rocket or navigate an endless sea. Yet, as a species we're curious enough, and fascinated enough by the prospect, to help pay for the trip and cheer at the explorer's return. Yes, we explore to find a better place to live or acquire a larger territory or make a fortune. But we also explore simply to discover what's there.

[B] "No other mammal2 moves around like we do," says Svante Paabo, a director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, where he uses genetics to study human origins. "We jump borders. We push into new territory even when we have resources where we are. Other animals don't do this ... In just 50,000 years, we covered everything. There's a kind of madness to it. Sailing out into the ocean, you have no idea what's on the other side. And, now, we go to Mars. We never stop. Why?"

[C] Why indeed? Paabo and other scientists examining this question are themselves explorers, walking new ground. They know that they might have to rethink their ideas at any time. They know that any ideas about why we explore might soon face revision as their young disciplines turn up new evidence. Yet, for those trying to figure out what makes humans tick, our drive to explore is an exciting subject. What gives rise to this "madness" to explore? What drove us out from Africa and on to the moon and beyond?

[D] If we are born with a drive to explore, perhaps the reason lies within our genes. In fact there is a variant of a gene called DRD4, which helps control dopamine,3 which is a chemical important in learning and reward. Researchers have tied the variant, known as DRD4-7R and carried by roughly 20 percent of all humans, to curiosity and restlessness. Dozens of human studies have found that 7R makes people more likely to take risks; explore new places, ideas, foods, relationships, drugs, or sexual opportunities, and generally welcome movement, change, and adventure. Studies in animals suggest that 7R increases their taste for both movement and new things.

[E] Several studies tie 7R to human migration. The first large genetic study to do so, led by Chuansheng Chen of the University of California, Irvine in 1999, found 7R more common in present-day migratory cultures than in settled ones. A larger 2011 study supported this, finding that 7R, along with another variant named 2R, tends to be found more frequently than you would expect by chance in populations whose ancestors migrated longer distances after they moved out of Africa. Neither study necessarily mean that the 7R form of the gene actually made those ancestors especially restless; you'd have to have been around back then to test that idea with certainty. But both studies support the idea that a nomadic4 lifestyle selects for the 7R variant.

[F] Another recent study backs this up. Among the Ariaal people in Africa, those who carry 7R tend to be stronger and better fed than those without 7R if they live in nomadic groups, possibly reflecting better fitness for a nomadic life. However, 7R carriers tend to be less well fed if they live in villages. The variant's value, then, like that of many genes and traits, may depend on the surroundings. A restless person may do well in an environment that often changes, but have trouble in a world where everything stays the same.

[G] So is 7R the explorer's gene or adventure gene, as some call it? Yale University evolutionary and population geneticist Kenneth Kidd thinks that exaggerates its role. Kidd speaks with special authority here, as he was part of the team that discovered the 7R variant 20 years ago. He thinks that many of the studies linking 7R to a nomadic life suffer from bad methods or math. He notes, too, that the pile of studies supporting 7R's link with these traits is countered by another pile showing no link.

[H] "You just can't reduce something as complex as human exploration to a single gene," he says, laughing. "Genetics doesn't work that way."

[I] It would be better, Kidd suggests, to consider how groups of genes might lay a foundation for such behavior. On this he and most 7R advocates agree: Whatever we ultimately conclude about 7R's role in driving restlessness, no one gene or set of genes can make us want to explore. More likely, different groups of genes contribute to multiple traits, some allowing us to explore, and others, 7R quite possibly among them, pressing us to do so. It helps, in short, to think not just of the drive to explore but of the ability, not just the motivation but the means. Before you can act on the drive, you need the tools or traits that make exploration possible.

1 Someone who is restless likes change and likes to try something new.

2 A mammal is an animal whose mother feeds it milk when it is young.

3 Dopamine is a chemical which the brain uses to send signals to nerve cells, and which is linked to feelings of reward or pleasure.

4 A person who is nomadic likes to travel and does not live long in one place.

Which would be the best alternative title for this passage?

Restless1 Genes

[A] The drive to see what lies beyond that far horizon or that ocean - or this planet - is a defining part of human identity and success. Not all of us ache to ride a rocket or navigate an endless sea. Yet, as a species we're curious enough, and fascinated enough by the prospect, to help pay for the trip and cheer at the explorer's return. Yes, we explore to find a better place to live or acquire a larger territory or make a fortune. But we also explore simply to discover what's there.

[B] "No other mammal2 moves around like we do," says Svante Paabo, a director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, where he uses genetics to study human origins. "We jump borders. We push into new territory even when we have resources where we are. Other animals don't do this ... In just 50,000 years, we covered everything. There's a kind of madness to it. Sailing out into the ocean, you have no idea what's on the other side. And, now, we go to Mars. We never stop. Why?"

[C] Why indeed? Paabo and other scientists examining this question are themselves explorers, walking new ground. They know that they might have to rethink their ideas at any time. They know that any ideas about why we explore might soon face revision as their young disciplines turn up new evidence. Yet, for those trying to figure out what makes humans tick, our drive to explore is an exciting subject. What gives rise to this "madness" to explore? What drove us out from Africa and on to the moon and beyond?

[D] If we are born with a drive to explore, perhaps the reason lies within our genes. In fact there is a variant of a gene called DRD4, which helps control dopamine,3 which is a chemical important in learning and reward. Researchers have tied the variant, known as DRD4-7R and carried by roughly 20 percent of all humans, to curiosity and restlessness. Dozens of human studies have found that 7R makes people more likely to take risks; explore new places, ideas, foods, relationships, drugs, or sexual opportunities, and generally welcome movement, change, and adventure. Studies in animals suggest that 7R increases their taste for both movement and new things.

[E] Several studies tie 7R to human migration. The first large genetic study to do so, led by Chuansheng Chen of the University of California, Irvine in 1999, found 7R more common in present-day migratory cultures than in settled ones. A larger 2011 study supported this, finding that 7R, along with another variant named 2R, tends to be found more frequently than you would expect by chance in populations whose ancestors migrated longer distances after they moved out of Africa. Neither study necessarily mean that the 7R form of the gene actually made those ancestors especially restless; you'd have to have been around back then to test that idea with certainty. But both studies support the idea that a nomadic4 lifestyle selects for the 7R variant.

[F] Another recent study backs this up. Among the Ariaal people in Africa, those who carry 7R tend to be stronger and better fed than those without 7R if they live in nomadic groups, possibly reflecting better fitness for a nomadic life. However, 7R carriers tend to be less well fed if they live in villages. The variant's value, then, like that of many genes and traits, may depend on the surroundings. A restless person may do well in an environment that often changes, but have trouble in a world where everything stays the same.

[G] So is 7R the explorer's gene or adventure gene, as some call it? Yale University evolutionary and population geneticist Kenneth Kidd thinks that exaggerates its role. Kidd speaks with special authority here, as he was part of the team that discovered the 7R variant 20 years ago. He thinks that many of the studies linking 7R to a nomadic life suffer from bad methods or math. He notes, too, that the pile of studies supporting 7R's link with these traits is countered by another pile showing no link.

[H] "You just can't reduce something as complex as human exploration to a single gene," he says, laughing. "Genetics doesn't work that way."

[I] It would be better, Kidd suggests, to consider how groups of genes might lay a foundation for such behavior. On this he and most 7R advocates agree: Whatever we ultimately conclude about 7R's role in driving restlessness, no one gene or set of genes can make us want to explore. More likely, different groups of genes contribute to multiple traits, some allowing us to explore, and others, 7R quite possibly among them, pressing us to do so. It helps, in short, to think not just of the drive to explore but of the ability, not just the motivation but the means. Before you can act on the drive, you need the tools or traits that make exploration possible.

1 Someone who is restless likes change and likes to try something new.

2 A mammal is an animal whose mother feeds it milk when it is young.

3 Dopamine is a chemical which the brain uses to send signals to nerve cells, and which is linked to feelings of reward or pleasure.

4 A person who is nomadic likes to travel and does not live long in one place.

Which of these sentences might Svante Paabo agree with?

Restless1 Genes

[A] The drive to see what lies beyond that far horizon or that ocean - or this planet - is a defining part of human identity and success. Not all of us ache to ride a rocket or navigate an endless sea. Yet, as a species we're curious enough, and fascinated enough by the prospect, to help pay for the trip and cheer at the explorer's return. Yes, we explore to find a better place to live or acquire a larger territory or make a fortune. But we also explore simply to discover what's there.

[B] "No other mammal2 moves around like we do," says Svante Paabo, a director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, where he uses genetics to study human origins. "We jump borders. We push into new territory even when we have resources where we are. Other animals don't do this ... In just 50,000 years, we covered everything. There's a kind of madness to it. Sailing out into the ocean, you have no idea what's on the other side. And, now, we go to Mars. We never stop. Why?"

[C] Why indeed? Paabo and other scientists examining this question are themselves explorers, walking new ground. They know that they might have to rethink their ideas at any time. They know that any ideas about why we explore might soon face revision as their young disciplines turn up new evidence. Yet, for those trying to figure out what makes humans tick, our drive to explore is an exciting subject. What gives rise to this "madness" to explore? What drove us out from Africa and on to the moon and beyond?

[D] If we are born with a drive to explore, perhaps the reason lies within our genes. In fact there is a variant of a gene called DRD4, which helps control dopamine,3 which is a chemical important in learning and reward. Researchers have tied the variant, known as DRD4-7R and carried by roughly 20 percent of all humans, to curiosity and restlessness. Dozens of human studies have found that 7R makes people more likely to take risks; explore new places, ideas, foods, relationships, drugs, or sexual opportunities, and generally welcome movement, change, and adventure. Studies in animals suggest that 7R increases their taste for both movement and new things.

[E] Several studies tie 7R to human migration. The first large genetic study to do so, led by Chuansheng Chen of the University of California, Irvine in 1999, found 7R more common in present-day migratory cultures than in settled ones. A larger 2011 study supported this, finding that 7R, along with another variant named 2R, tends to be found more frequently than you would expect by chance in populations whose ancestors migrated longer distances after they moved out of Africa. Neither study necessarily mean that the 7R form of the gene actually made those ancestors especially restless; you'd have to have been around back then to test that idea with certainty. But both studies support the idea that a nomadic4 lifestyle selects for the 7R variant.

[F] Another recent study backs this up. Among the Ariaal people in Africa, those who carry 7R tend to be stronger and better fed than those without 7R if they live in nomadic groups, possibly reflecting better fitness for a nomadic life. However, 7R carriers tend to be less well fed if they live in villages. The variant's value, then, like that of many genes and traits, may depend on the surroundings. A restless person may do well in an environment that often changes, but have trouble in a world where everything stays the same.

[G] So is 7R the explorer's gene or adventure gene, as some call it? Yale University evolutionary and population geneticist Kenneth Kidd thinks that exaggerates its role. Kidd speaks with special authority here, as he was part of the team that discovered the 7R variant 20 years ago. He thinks that many of the studies linking 7R to a nomadic life suffer from bad methods or math. He notes, too, that the pile of studies supporting 7R's link with these traits is countered by another pile showing no link.

[H] "You just can't reduce something as complex as human exploration to a single gene," he says, laughing. "Genetics doesn't work that way."

[I] It would be better, Kidd suggests, to consider how groups of genes might lay a foundation for such behavior. On this he and most 7R advocates agree: Whatever we ultimately conclude about 7R's role in driving restlessness, no one gene or set of genes can make us want to explore. More likely, different groups of genes contribute to multiple traits, some allowing us to explore, and others, 7R quite possibly among them, pressing us to do so. It helps, in short, to think not just of the drive to explore but of the ability, not just the motivation but the means. Before you can act on the drive, you need the tools or traits that make exploration possible.

1 Someone who is restless likes change and likes to try something new.

2 A mammal is an animal whose mother feeds it milk when it is young.

3 Dopamine is a chemical which the brain uses to send signals to nerve cells, and which is linked to feelings of reward or pleasure.

4 A person who is nomadic likes to travel and does not live long in one place.

In paragraph C, what does the phrase what makes humans tick mean?

Restless1 Genes

[A] The drive to see what lies beyond that far horizon or that ocean - or this planet - is a defining part of human identity and success. Not all of us ache to ride a rocket or navigate an endless sea. Yet, as a species we're curious enough, and fascinated enough by the prospect, to help pay for the trip and cheer at the explorer's return. Yes, we explore to find a better place to live or acquire a larger territory or make a fortune. But we also explore simply to discover what's there.

[B] "No other mammal2 moves around like we do," says Svante Paabo, a director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, where he uses genetics to study human origins. "We jump borders. We push into new territory even when we have resources where we are. Other animals don't do this ... In just 50,000 years, we covered everything. There's a kind of madness to it. Sailing out into the ocean, you have no idea what's on the other side. And, now, we go to Mars. We never stop. Why?"

[C] Why indeed? Paabo and other scientists examining this question are themselves explorers, walking new ground. They know that they might have to rethink their ideas at any time. They know that any ideas about why we explore might soon face revision as their young disciplines turn up new evidence. Yet, for those trying to figure out what makes humans tick, our drive to explore is an exciting subject. What gives rise to this "madness" to explore? What drove us out from Africa and on to the moon and beyond?

[D] If we are born with a drive to explore, perhaps the reason lies within our genes. In fact there is a variant of a gene called DRD4, which helps control dopamine,3 which is a chemical important in learning and reward. Researchers have tied the variant, known as DRD4-7R and carried by roughly 20 percent of all humans, to curiosity and restlessness. Dozens of human studies have found that 7R makes people more likely to take risks; explore new places, ideas, foods, relationships, drugs, or sexual opportunities, and generally welcome movement, change, and adventure. Studies in animals suggest that 7R increases their taste for both movement and new things.

[E] Several studies tie 7R to human migration. The first large genetic study to do so, led by Chuansheng Chen of the University of California, Irvine in 1999, found 7R more common in present-day migratory cultures than in settled ones. A larger 2011 study supported this, finding that 7R, along with another variant named 2R, tends to be found more frequently than you would expect by chance in populations whose ancestors migrated longer distances after they moved out of Africa. Neither study necessarily mean that the 7R form of the gene actually made those ancestors especially restless; you'd have to have been around back then to test that idea with certainty. But both studies support the idea that a nomadic4 lifestyle selects for the 7R variant.

[F] Another recent study backs this up. Among the Ariaal people in Africa, those who carry 7R tend to be stronger and better fed than those without 7R if they live in nomadic groups, possibly reflecting better fitness for a nomadic life. However, 7R carriers tend to be less well fed if they live in villages. The variant's value, then, like that of many genes and traits, may depend on the surroundings. A restless person may do well in an environment that often changes, but have trouble in a world where everything stays the same.

[G] So is 7R the explorer's gene or adventure gene, as some call it? Yale University evolutionary and population geneticist Kenneth Kidd thinks that exaggerates its role. Kidd speaks with special authority here, as he was part of the team that discovered the 7R variant 20 years ago. He thinks that many of the studies linking 7R to a nomadic life suffer from bad methods or math. He notes, too, that the pile of studies supporting 7R's link with these traits is countered by another pile showing no link.

[H] "You just can't reduce something as complex as human exploration to a single gene," he says, laughing. "Genetics doesn't work that way."

[I] It would be better, Kidd suggests, to consider how groups of genes might lay a foundation for such behavior. On this he and most 7R advocates agree: Whatever we ultimately conclude about 7R's role in driving restlessness, no one gene or set of genes can make us want to explore. More likely, different groups of genes contribute to multiple traits, some allowing us to explore, and others, 7R quite possibly among them, pressing us to do so. It helps, in short, to think not just of the drive to explore but of the ability, not just the motivation but the means. Before you can act on the drive, you need the tools or traits that make exploration possible.

1 Someone who is restless likes change and likes to try something new.

2 A mammal is an animal whose mother feeds it milk when it is young.

3 Dopamine is a chemical which the brain uses to send signals to nerve cells, and which is linked to feelings of reward or pleasure.

4 A person who is nomadic likes to travel and does not live long in one place.

What is true of Ariaal people who do not have the 7R gene and live in nomadic groups?

Restless1 Genes

[A] The drive to see what lies beyond that far horizon or that ocean - or this planet - is a defining part of human identity and success. Not all of us ache to ride a rocket or navigate an endless sea. Yet, as a species we're curious enough, and fascinated enough by the prospect, to help pay for the trip and cheer at the explorer's return. Yes, we explore to find a better place to live or acquire a larger territory or make a fortune. But we also explore simply to discover what's there.

[B] "No other mammal2 moves around like we do," says Svante Paabo, a director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, where he uses genetics to study human origins. "We jump borders. We push into new territory even when we have resources where we are. Other animals don't do this ... In just 50,000 years, we covered everything. There's a kind of madness to it. Sailing out into the ocean, you have no idea what's on the other side. And, now, we go to Mars. We never stop. Why?"

[C] Why indeed? Paabo and other scientists examining this question are themselves explorers, walking new ground. They know that they might have to rethink their ideas at any time. They know that any ideas about why we explore might soon face revision as their young disciplines turn up new evidence. Yet, for those trying to figure out what makes humans tick, our drive to explore is an exciting subject. What gives rise to this "madness" to explore? What drove us out from Africa and on to the moon and beyond?

[D] If we are born with a drive to explore, perhaps the reason lies within our genes. In fact there is a variant of a gene called DRD4, which helps control dopamine,3 which is a chemical important in learning and reward. Researchers have tied the variant, known as DRD4-7R and carried by roughly 20 percent of all humans, to curiosity and restlessness. Dozens of human studies have found that 7R makes people more likely to take risks; explore new places, ideas, foods, relationships, drugs, or sexual opportunities, and generally welcome movement, change, and adventure. Studies in animals suggest that 7R increases their taste for both movement and new things.

[E] Several studies tie 7R to human migration. The first large genetic study to do so, led by Chuansheng Chen of the University of California, Irvine in 1999, found 7R more common in present-day migratory cultures than in settled ones. A larger 2011 study supported this, finding that 7R, along with another variant named 2R, tends to be found more frequently than you would expect by chance in populations whose ancestors migrated longer distances after they moved out of Africa. Neither study necessarily mean that the 7R form of the gene actually made those ancestors especially restless; you'd have to have been around back then to test that idea with certainty. But both studies support the idea that a nomadic4 lifestyle selects for the 7R variant.

[F] Another recent study backs this up. Among the Ariaal people in Africa, those who carry 7R tend to be stronger and better fed than those without 7R if they live in nomadic groups, possibly reflecting better fitness for a nomadic life. However, 7R carriers tend to be less well fed if they live in villages. The variant's value, then, like that of many genes and traits, may depend on the surroundings. A restless person may do well in an environment that often changes, but have trouble in a world where everything stays the same.

[G] So is 7R the explorer's gene or adventure gene, as some call it? Yale University evolutionary and population geneticist Kenneth Kidd thinks that exaggerates its role. Kidd speaks with special authority here, as he was part of the team that discovered the 7R variant 20 years ago. He thinks that many of the studies linking 7R to a nomadic life suffer from bad methods or math. He notes, too, that the pile of studies supporting 7R's link with these traits is countered by another pile showing no link.

[H] "You just can't reduce something as complex as human exploration to a single gene," he says, laughing. "Genetics doesn't work that way."

[I] It would be better, Kidd suggests, to consider how groups of genes might lay a foundation for such behavior. On this he and most 7R advocates agree: Whatever we ultimately conclude about 7R's role in driving restlessness, no one gene or set of genes can make us want to explore. More likely, different groups of genes contribute to multiple traits, some allowing us to explore, and others, 7R quite possibly among them, pressing us to do so. It helps, in short, to think not just of the drive to explore but of the ability, not just the motivation but the means. Before you can act on the drive, you need the tools or traits that make exploration possible.

1 Someone who is restless likes change and likes to try something new.

2 A mammal is an animal whose mother feeds it milk when it is young.

3 Dopamine is a chemical which the brain uses to send signals to nerve cells, and which is linked to feelings of reward or pleasure.

4 A person who is nomadic likes to travel and does not live long in one place.

Which of these sentences might Kenneth Kidd agree with?

Restless1 Genes

[A] The drive to see what lies beyond that far horizon or that ocean - or this planet - is a defining part of human identity and success. Not all of us ache to ride a rocket or navigate an endless sea. Yet, as a species we're curious enough, and fascinated enough by the prospect, to help pay for the trip and cheer at the explorer's return. Yes, we explore to find a better place to live or acquire a larger territory or make a fortune. But we also explore simply to discover what's there.

[B] "No other mammal2 moves around like we do," says Svante Paabo, a director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, where he uses genetics to study human origins. "We jump borders. We push into new territory even when we have resources where we are. Other animals don't do this ... In just 50,000 years, we covered everything. There's a kind of madness to it. Sailing out into the ocean, you have no idea what's on the other side. And, now, we go to Mars. We never stop. Why?"

[C] Why indeed? Paabo and other scientists examining this question are themselves explorers, walking new ground. They know that they might have to rethink their ideas at any time. They know that any ideas about why we explore might soon face revision as their young disciplines turn up new evidence. Yet, for those trying to figure out what makes humans tick, our drive to explore is an exciting subject. What gives rise to this "madness" to explore? What drove us out from Africa and on to the moon and beyond?

[D] If we are born with a drive to explore, perhaps the reason lies within our genes. In fact there is a variant of a gene called DRD4, which helps control dopamine,3 which is a chemical important in learning and reward. Researchers have tied the variant, known as DRD4-7R and carried by roughly 20 percent of all humans, to curiosity and restlessness. Dozens of human studies have found that 7R makes people more likely to take risks; explore new places, ideas, foods, relationships, drugs, or sexual opportunities, and generally welcome movement, change, and adventure. Studies in animals suggest that 7R increases their taste for both movement and new things.

[E] Several studies tie 7R to human migration. The first large genetic study to do so, led by Chuansheng Chen of the University of California, Irvine in 1999, found 7R more common in present-day migratory cultures than in settled ones. A larger 2011 study supported this, finding that 7R, along with another variant named 2R, tends to be found more frequently than you would expect by chance in populations whose ancestors migrated longer distances after they moved out of Africa. Neither study necessarily mean that the 7R form of the gene actually made those ancestors especially restless; you'd have to have been around back then to test that idea with certainty. But both studies support the idea that a nomadic4 lifestyle selects for the 7R variant.

[F] Another recent study backs this up. Among the Ariaal people in Africa, those who carry 7R tend to be stronger and better fed than those without 7R if they live in nomadic groups, possibly reflecting better fitness for a nomadic life. However, 7R carriers tend to be less well fed if they live in villages. The variant's value, then, like that of many genes and traits, may depend on the surroundings. A restless person may do well in an environment that often changes, but have trouble in a world where everything stays the same.

[G] So is 7R the explorer's gene or adventure gene, as some call it? Yale University evolutionary and population geneticist Kenneth Kidd thinks that exaggerates its role. Kidd speaks with special authority here, as he was part of the team that discovered the 7R variant 20 years ago. He thinks that many of the studies linking 7R to a nomadic life suffer from bad methods or math. He notes, too, that the pile of studies supporting 7R's link with these traits is countered by another pile showing no link.

[H] "You just can't reduce something as complex as human exploration to a single gene," he says, laughing. "Genetics doesn't work that way."

[I] It would be better, Kidd suggests, to consider how groups of genes might lay a foundation for such behavior. On this he and most 7R advocates agree: Whatever we ultimately conclude about 7R's role in driving restlessness, no one gene or set of genes can make us want to explore. More likely, different groups of genes contribute to multiple traits, some allowing us to explore, and others, 7R quite possibly among them, pressing us to do so. It helps, in short, to think not just of the drive to explore but of the ability, not just the motivation but the means. Before you can act on the drive, you need the tools or traits that make exploration possible.

1 Someone who is restless likes change and likes to try something new.

2 A mammal is an animal whose mother feeds it milk when it is young.

3 Dopamine is a chemical which the brain uses to send signals to nerve cells, and which is linked to feelings of reward or pleasure.

4 A person who is nomadic likes to travel and does not live long in one place.

Is the following sentence fact or speculation?

Researchers have tied the variant, known as DRD4-7R and carried by roughly 20 percent of all humans, to curiosity and restlessness.

Restless1 Genes

[A] The drive to see what lies beyond that far horizon or that ocean - or this planet - is a defining part of human identity and success. Not all of us ache to ride a rocket or navigate an endless sea. Yet, as a species we're curious enough, and fascinated enough by the prospect, to help pay for the trip and cheer at the explorer's return. Yes, we explore to find a better place to live or acquire a larger territory or make a fortune. But we also explore simply to discover what's there.

[B] "No other mammal2 moves around like we do," says Svante Paabo, a director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, where he uses genetics to study human origins. "We jump borders. We push into new territory even when we have resources where we are. Other animals don't do this ... In just 50,000 years, we covered everything. There's a kind of madness to it. Sailing out into the ocean, you have no idea what's on the other side. And, now, we go to Mars. We never stop. Why?"

[C] Why indeed? Paabo and other scientists examining this question are themselves explorers, walking new ground. They know that they might have to rethink their ideas at any time. They know that any ideas about why we explore might soon face revision as their young disciplines turn up new evidence. Yet, for those trying to figure out what makes humans tick, our drive to explore is an exciting subject. What gives rise to this "madness" to explore? What drove us out from Africa and on to the moon and beyond?

[D] If we are born with a drive to explore, perhaps the reason lies within our genes. In fact there is a variant of a gene called DRD4, which helps control dopamine,3 which is a chemical important in learning and reward. Researchers have tied the variant, known as DRD4-7R and carried by roughly 20 percent of all humans, to curiosity and restlessness. Dozens of human studies have found that 7R makes people more likely to take risks; explore new places, ideas, foods, relationships, drugs, or sexual opportunities, and generally welcome movement, change, and adventure. Studies in animals suggest that 7R increases their taste for both movement and new things.

[E] Several studies tie 7R to human migration. The first large genetic study to do so, led by Chuansheng Chen of the University of California, Irvine in 1999, found 7R more common in present-day migratory cultures than in settled ones. A larger 2011 study supported this, finding that 7R, along with another variant named 2R, tends to be found more frequently than you would expect by chance in populations whose ancestors migrated longer distances after they moved out of Africa. Neither study necessarily mean that the 7R form of the gene actually made those ancestors especially restless; you'd have to have been around back then to test that idea with certainty. But both studies support the idea that a nomadic4 lifestyle selects for the 7R variant.

[F] Another recent study backs this up. Among the Ariaal people in Africa, those who carry 7R tend to be stronger and better fed than those without 7R if they live in nomadic groups, possibly reflecting better fitness for a nomadic life. However, 7R carriers tend to be less well fed if they live in villages. The variant's value, then, like that of many genes and traits, may depend on the surroundings. A restless person may do well in an environment that often changes, but have trouble in a world where everything stays the same.

[G] So is 7R the explorer's gene or adventure gene, as some call it? Yale University evolutionary and population geneticist Kenneth Kidd thinks that exaggerates its role. Kidd speaks with special authority here, as he was part of the team that discovered the 7R variant 20 years ago. He thinks that many of the studies linking 7R to a nomadic life suffer from bad methods or math. He notes, too, that the pile of studies supporting 7R's link with these traits is countered by another pile showing no link.

[H] "You just can't reduce something as complex as human exploration to a single gene," he says, laughing. "Genetics doesn't work that way."

[I] It would be better, Kidd suggests, to consider how groups of genes might lay a foundation for such behavior. On this he and most 7R advocates agree: Whatever we ultimately conclude about 7R's role in driving restlessness, no one gene or set of genes can make us want to explore. More likely, different groups of genes contribute to multiple traits, some allowing us to explore, and others, 7R quite possibly among them, pressing us to do so. It helps, in short, to think not just of the drive to explore but of the ability, not just the motivation but the means. Before you can act on the drive, you need the tools or traits that make exploration possible.

1 Someone who is restless likes change and likes to try something new.

2 A mammal is an animal whose mother feeds it milk when it is young.

3 Dopamine is a chemical which the brain uses to send signals to nerve cells, and which is linked to feelings of reward or pleasure.

4 A person who is nomadic likes to travel and does not live long in one place.

Is the following sentence fact or speculation?

Dozens of human studies have found that 7R makes people more likely to take risks ...

Restless1 Genes

[A] The drive to see what lies beyond that far horizon or that ocean - or this planet - is a defining part of human identity and success. Not all of us ache to ride a rocket or navigate an endless sea. Yet, as a species we're curious enough, and fascinated enough by the prospect, to help pay for the trip and cheer at the explorer's return. Yes, we explore to find a better place to live or acquire a larger territory or make a fortune. But we also explore simply to discover what's there.

[B] "No other mammal2 moves around like we do," says Svante Paabo, a director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, where he uses genetics to study human origins. "We jump borders. We push into new territory even when we have resources where we are. Other animals don't do this ... In just 50,000 years, we covered everything. There's a kind of madness to it. Sailing out into the ocean, you have no idea what's on the other side. And, now, we go to Mars. We never stop. Why?"

[C] Why indeed? Paabo and other scientists examining this question are themselves explorers, walking new ground. They know that they might have to rethink their ideas at any time. They know that any ideas about why we explore might soon face revision as their young disciplines turn up new evidence. Yet, for those trying to figure out what makes humans tick, our drive to explore is an exciting subject. What gives rise to this "madness" to explore? What drove us out from Africa and on to the moon and beyond?

[D] If we are born with a drive to explore, perhaps the reason lies within our genes. In fact there is a variant of a gene called DRD4, which helps control dopamine,3 which is a chemical important in learning and reward. Researchers have tied the variant, known as DRD4-7R and carried by roughly 20 percent of all humans, to curiosity and restlessness. Dozens of human studies have found that 7R makes people more likely to take risks; explore new places, ideas, foods, relationships, drugs, or sexual opportunities, and generally welcome movement, change, and adventure. Studies in animals suggest that 7R increases their taste for both movement and new things.

[E] Several studies tie 7R to human migration. The first large genetic study to do so, led by Chuansheng Chen of the University of California, Irvine in 1999, found 7R more common in present-day migratory cultures than in settled ones. A larger 2011 study supported this, finding that 7R, along with another variant named 2R, tends to be found more frequently than you would expect by chance in populations whose ancestors migrated longer distances after they moved out of Africa. Neither study necessarily mean that the 7R form of the gene actually made those ancestors especially restless; you'd have to have been around back then to test that idea with certainty. But both studies support the idea that a nomadic4 lifestyle selects for the 7R variant.

[F] Another recent study backs this up. Among the Ariaal people in Africa, those who carry 7R tend to be stronger and better fed than those without 7R if they live in nomadic groups, possibly reflecting better fitness for a nomadic life. However, 7R carriers tend to be less well fed if they live in villages. The variant's value, then, like that of many genes and traits, may depend on the surroundings. A restless person may do well in an environment that often changes, but have trouble in a world where everything stays the same.

[G] So is 7R the explorer's gene or adventure gene, as some call it? Yale University evolutionary and population geneticist Kenneth Kidd thinks that exaggerates its role. Kidd speaks with special authority here, as he was part of the team that discovered the 7R variant 20 years ago. He thinks that many of the studies linking 7R to a nomadic life suffer from bad methods or math. He notes, too, that the pile of studies supporting 7R's link with these traits is countered by another pile showing no link.

[H] "You just can't reduce something as complex as human exploration to a single gene," he says, laughing. "Genetics doesn't work that way."

[I] It would be better, Kidd suggests, to consider how groups of genes might lay a foundation for such behavior. On this he and most 7R advocates agree: Whatever we ultimately conclude about 7R's role in driving restlessness, no one gene or set of genes can make us want to explore. More likely, different groups of genes contribute to multiple traits, some allowing us to explore, and others, 7R quite possibly among them, pressing us to do so. It helps, in short, to think not just of the drive to explore but of the ability, not just the motivation but the means. Before you can act on the drive, you need the tools or traits that make exploration possible.

1 Someone who is restless likes change and likes to try something new.

2 A mammal is an animal whose mother feeds it milk when it is young.

3 Dopamine is a chemical which the brain uses to send signals to nerve cells, and which is linked to feelings of reward or pleasure.

4 A person who is nomadic likes to travel and does not live long in one place.

Is the following sentence fact or speculation?

A restless person may do well in an environment that often changes, but have trouble in a world where everything stays the same.

Restless1 Genes

[A] The drive to see what lies beyond that far horizon or that ocean - or this planet - is a defining part of human identity and success. Not all of us ache to ride a rocket or navigate an endless sea. Yet, as a species we're curious enough, and fascinated enough by the prospect, to help pay for the trip and cheer at the explorer's return. Yes, we explore to find a better place to live or acquire a larger territory or make a fortune. But we also explore simply to discover what's there.

[B] "No other mammal2 moves around like we do," says Svante Paabo, a director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, where he uses genetics to study human origins. "We jump borders. We push into new territory even when we have resources where we are. Other animals don't do this ... In just 50,000 years, we covered everything. There's a kind of madness to it. Sailing out into the ocean, you have no idea what's on the other side. And, now, we go to Mars. We never stop. Why?"

[C] Why indeed? Paabo and other scientists examining this question are themselves explorers, walking new ground. They know that they might have to rethink their ideas at any time. They know that any ideas about why we explore might soon face revision as their young disciplines turn up new evidence. Yet, for those trying to figure out what makes humans tick, our drive to explore is an exciting subject. What gives rise to this "madness" to explore? What drove us out from Africa and on to the moon and beyond?

[D] If we are born with a drive to explore, perhaps the reason lies within our genes. In fact there is a variant of a gene called DRD4, which helps control dopamine,3 which is a chemical important in learning and reward. Researchers have tied the variant, known as DRD4-7R and carried by roughly 20 percent of all humans, to curiosity and restlessness. Dozens of human studies have found that 7R makes people more likely to take risks; explore new places, ideas, foods, relationships, drugs, or sexual opportunities, and generally welcome movement, change, and adventure. Studies in animals suggest that 7R increases their taste for both movement and new things.

[E] Several studies tie 7R to human migration. The first large genetic study to do so, led by Chuansheng Chen of the University of California, Irvine in 1999, found 7R more common in present-day migratory cultures than in settled ones. A larger 2011 study supported this, finding that 7R, along with another variant named 2R, tends to be found more frequently than you would expect by chance in populations whose ancestors migrated longer distances after they moved out of Africa. Neither study necessarily mean that the 7R form of the gene actually made those ancestors especially restless; you'd have to have been around back then to test that idea with certainty. But both studies support the idea that a nomadic4 lifestyle selects for the 7R variant.

[F] Another recent study backs this up. Among the Ariaal people in Africa, those who carry 7R tend to be stronger and better fed than those without 7R if they live in nomadic groups, possibly reflecting better fitness for a nomadic life. However, 7R carriers tend to be less well fed if they live in villages. The variant's value, then, like that of many genes and traits, may depend on the surroundings. A restless person may do well in an environment that often changes, but have trouble in a world where everything stays the same.

[G] So is 7R the explorer's gene or adventure gene, as some call it? Yale University evolutionary and population geneticist Kenneth Kidd thinks that exaggerates its role. Kidd speaks with special authority here, as he was part of the team that discovered the 7R variant 20 years ago. He thinks that many of the studies linking 7R to a nomadic life suffer from bad methods or math. He notes, too, that the pile of studies supporting 7R's link with these traits is countered by another pile showing no link.

[H] "You just can't reduce something as complex as human exploration to a single gene," he says, laughing. "Genetics doesn't work that way."

[I] It would be better, Kidd suggests, to consider how groups of genes might lay a foundation for such behavior. On this he and most 7R advocates agree: Whatever we ultimately conclude about 7R's role in driving restlessness, no one gene or set of genes can make us want to explore. More likely, different groups of genes contribute to multiple traits, some allowing us to explore, and others, 7R quite possibly among them, pressing us to do so. It helps, in short, to think not just of the drive to explore but of the ability, not just the motivation but the means. Before you can act on the drive, you need the tools or traits that make exploration possible.

1 Someone who is restless likes change and likes to try something new.

2 A mammal is an animal whose mother feeds it milk when it is young.

3 Dopamine is a chemical which the brain uses to send signals to nerve cells, and which is linked to feelings of reward or pleasure.

4 A person who is nomadic likes to travel and does not live long in one place.

Is the following sentence fact or speculation?

He notes, too, that the pile of studies supporting 7R's link with these traits is countered by another pile showing no link.

Restless1 Genes

[A] The drive to see what lies beyond that far horizon or that ocean - or this planet - is a defining part of human identity and success. Not all of us ache to ride a rocket or navigate an endless sea. Yet, as a species we're curious enough, and fascinated enough by the prospect, to help pay for the trip and cheer at the explorer's return. Yes, we explore to find a better place to live or acquire a larger territory or make a fortune. But we also explore simply to discover what's there.

[B] "No other mammal2 moves around like we do," says Svante Paabo, a director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, where he uses genetics to study human origins. "We jump borders. We push into new territory even when we have resources where we are. Other animals don't do this ... In just 50,000 years, we covered everything. There's a kind of madness to it. Sailing out into the ocean, you have no idea what's on the other side. And, now, we go to Mars. We never stop. Why?"

[C] Why indeed? Paabo and other scientists examining this question are themselves explorers, walking new ground. They know that they might have to rethink their ideas at any time. They know that any ideas about why we explore might soon face revision as their young disciplines turn up new evidence. Yet, for those trying to figure out what makes humans tick, our drive to explore is an exciting subject. What gives rise to this "madness" to explore? What drove us out from Africa and on to the moon and beyond?

[D] If we are born with a drive to explore, perhaps the reason lies within our genes. In fact there is a variant of a gene called DRD4, which helps control dopamine,3 which is a chemical important in learning and reward. Researchers have tied the variant, known as DRD4-7R and carried by roughly 20 percent of all humans, to curiosity and restlessness. Dozens of human studies have found that 7R makes people more likely to take risks; explore new places, ideas, foods, relationships, drugs, or sexual opportunities, and generally welcome movement, change, and adventure. Studies in animals suggest that 7R increases their taste for both movement and new things.

[E] Several studies tie 7R to human migration. The first large genetic study to do so, led by Chuansheng Chen of the University of California, Irvine in 1999, found 7R more common in present-day migratory cultures than in settled ones. A larger 2011 study supported this, finding that 7R, along with another variant named 2R, tends to be found more frequently than you would expect by chance in populations whose ancestors migrated longer distances after they moved out of Africa. Neither study necessarily mean that the 7R form of the gene actually made those ancestors especially restless; you'd have to have been around back then to test that idea with certainty. But both studies support the idea that a nomadic4 lifestyle selects for the 7R variant.

[F] Another recent study backs this up. Among the Ariaal people in Africa, those who carry 7R tend to be stronger and better fed than those without 7R if they live in nomadic groups, possibly reflecting better fitness for a nomadic life. However, 7R carriers tend to be less well fed if they live in villages. The variant's value, then, like that of many genes and traits, may depend on the surroundings. A restless person may do well in an environment that often changes, but have trouble in a world where everything stays the same.

[G] So is 7R the explorer's gene or adventure gene, as some call it? Yale University evolutionary and population geneticist Kenneth Kidd thinks that exaggerates its role. Kidd speaks with special authority here, as he was part of the team that discovered the 7R variant 20 years ago. He thinks that many of the studies linking 7R to a nomadic life suffer from bad methods or math. He notes, too, that the pile of studies supporting 7R's link with these traits is countered by another pile showing no link.

[H] "You just can't reduce something as complex as human exploration to a single gene," he says, laughing. "Genetics doesn't work that way."

[I] It would be better, Kidd suggests, to consider how groups of genes might lay a foundation for such behavior. On this he and most 7R advocates agree: Whatever we ultimately conclude about 7R's role in driving restlessness, no one gene or set of genes can make us want to explore. More likely, different groups of genes contribute to multiple traits, some allowing us to explore, and others, 7R quite possibly among them, pressing us to do so. It helps, in short, to think not just of the drive to explore but of the ability, not just the motivation but the means. Before you can act on the drive, you need the tools or traits that make exploration possible.

1 Someone who is restless likes change and likes to try something new.

2 A mammal is an animal whose mother feeds it milk when it is young.

3 Dopamine is a chemical which the brain uses to send signals to nerve cells, and which is linked to feelings of reward or pleasure.

4 A person who is nomadic likes to travel and does not live long in one place.

Is the following sentence fact or speculation?

More likely, different groups of genes contribute to multiple traits, some allowing us to explore, and others, 7R quite possibly among them, pressing us to do so.

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