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            Since there is such an abundance of food in the sea, it is understandable that some the efficient, highly adaptable, warm - blooded mammals that evolved on land should have returned to the sea. Those that did have flourished Within about 50 million years - no time at all, geologically speaking - one of the four kinds of mammals that has returned to a marine environment has developed into the largest of all animal forms, the whale. A second kind, the seal, has produced what is probably the greatest population of large carnivorous mammals on Earth. This suggests that these "top dogs" of the ocean are prospering and multiplying. However, such has not been the case, at least not for the last 150 years. Trouble has closed in or these mammals in the form of equally warm-blooded and even more efficient and adaptable predators, humans. At sea, as on land, humans have now positioned themselves on to -of the whole great pyramid of life, and they have caused serious problems for the mammals of the sea.

 

          There is a simple reason for this. Marine mammals have the misfortune to be swimming aggregates of commodities that humans want: fur, oil, and meat. Even so, they might not be so vulnerable to human depredation if they did not, like humans, reproduce so slowly. Every year humans take more than 50 million tons of fish from the oceans without critically depleting the population of any species. But the slow-breeding mammals of the sea have been all but wiped out by humans seeking to satisfy their wants and whims.

Which of the following statements about marine mammals best expresses the main idea of the passage

• They have their origins on land.

• They have evolved successfully but are now threatened by humans.

• They compete with one another for the ocean's food supply.

• They have many of the biological traits of humans.

   

Since there is such an abundance of food in the sea, it is understandable that some the efficient, highly adaptable, warm - blooded mammals that evolved on land should have returned to the sea. Those that did have flourished Within about 50 million years - no time at all, geologically speaking - one of the four kinds of mammals that has returned to a marine environment has developed into the largest of all animal forms, the whale. A second kind, the seal, has produced what is probably the greatest population of large carnivorous mammals on Earth. This suggests that these "top dogs" of the ocean are prospering and multiplying. However, such has not been the case, at least not for the last 150 years. Trouble has closed in or these mammals in the form of equally warm-blooded and even more efficient and adaptable predators, humans. At sea, as on land, humans have now positioned themselves on to -of the whole great pyramid of life, and they have caused serious problems for the mammals of the sea.

 

          There is a simple reason for this. Marine mammals have the misfortune to be swimming aggregates of commodities that humans want: fur, oil, and meat. Even so, they might not be so vulnerable to human depredation if they did not, like humans, reproduce so slowly. Every year humans take more than 50 million tons of fish from the oceans without critically depleting the population of any species. But the slow-breeding mammals of the sea have been all but wiped out by humans seeking to satisfy their wants and whims.

What advantage did some land mammals gain by returning to the sea?

• Fewer predators exist in the sea

• More space is available in the sea

• There is a greater supply of food in the sea

• The climate is more hospitable in the sea.

   

            Since there is such an abundance of food in the sea, it is understandable that some the efficient, highly adaptable, warm - blooded mammals that evolved on land should have returned to the sea. Those that did have flourished Within about 50 million years - no time at all, geologically speaking - one of the four kinds of mammals that has returned to a marine environment has developed into the largest of all animal forms, the whale. A second kind, the seal, has produced what is probably the greatest population of large carnivorous mammals on Earth. This suggests that these "top dogs" of the ocean are prospering and multiplying. However, such has not been the case, at least not for the last 150 years. Trouble has closed in or these mammals in the form of equally warm-blooded and even more efficient and adaptable predators, humans. At sea, as on land, humans have now positioned themselves on to -of the whole great pyramid of life, and they have caused serious problems for the mammals of the sea.

 

          There is a simple reason for this. Marine mammals have the misfortune to be swimming aggregates of commodities that humans want: fur, oil, and meat. Even so, they might not be so vulnerable to human depredation if they did not, like humans, reproduce so slowly. Every year humans take more than 50 million tons of fish from the oceans without critically depleting the population of any species. But the slow-breeding mammals of the sea have been all but wiped out by humans seeking to satisfy their wants and whims.

It can be inferred from the passage that during the last 150 years humans have...

• constructed submarines

• learned how to swim

• threatened the existence of some marine mammals

• begun to harvest certain plants from the ocean as food

            Since there is such an abundance of food in the sea, it is understandable that some the efficient, highly adaptable, warm - blooded mammals that evolved on land should have returned to the sea. Those that did have flourished Within about 50 million years - no time at all, geologically speaking - one of the four kinds of mammals that has returned to a marine environment has developed into the largest of all animal forms, the whale. A second kind, the seal, has produced what is probably the greatest population of large carnivorous mammals on Earth. This suggests that these "top dogs" of the ocean are prospering and multiplying. However, such has not been the case, at least not for the last 150 years. Trouble has closed in or these mammals in the form of equally warm-blooded and even more efficient and adaptable predators, humans. At sea, as on land, humans have now positioned themselves on to -of the whole great pyramid of life, and they have caused serious problems for the mammals of the sea.

 

          There is a simple reason for this. Marine mammals have the misfortune to be swimming aggregates of commodities that humans want: fur, oil, and meat. Even so, they might not be so vulnerable to human depredation if they did not, like humans, reproduce so slowly. Every year humans take more than 50 million tons of fish from the oceans without critically depleting the population of any species. But the slow-breeding mammals of the sea have been all but wiped out by humans seeking to satisfy their wants and whims.

In line 14 the word "they" refers to

• marine mammals

• commodities

• humans

• fur. oil. and meat

            Since there is such an abundance of food in the sea, it is understandable that some the efficient, highly adaptable, warm - blooded mammals that evolved on land should have returned to the sea. Those that did have flourished Within about 50 million years - no time at all, geologically speaking - one of the four kinds of mammals that has returned to a marine environment has developed into the largest of all animal forms, the whale. A second kind, the seal, has produced what is probably the greatest population of large carnivorous mammals on Earth. This suggests that these "top dogs" of the ocean are prospering and multiplying. However, such has not been the case, at least not for the last 150 years. Trouble has closed in or these mammals in the form of equally warm-blooded and even more efficient and adaptable predators, humans. At sea, as on land, humans have now positioned themselves on to -of the whole great pyramid of life, and they have caused serious problems for the mammals of the sea.

 

          There is a simple reason for this. Marine mammals have the misfortune to be swimming aggregates of commodities that humans want: fur, oil, and meat. Even so, they might not be so vulnerable to human depredation if they did not, like humans, reproduce so slowly. Every year humans take more than 50 million tons of fish from the oceans without critically depleting the population of any species. But the slow-breeding mammals of the sea have been all but wiped out by humans seeking to satisfy their wants and whims.

Which of the following statements is supported by the passage?

• The whale's ancestors were driven into the sea by humans

• The food supply of seals is being depleted by humans

• The whale evolved from a species of land - dwelling mammal.

• Whales are a more efficient and adapt-able species than humans.

            Since there is such an abundance of food in the sea, it is understandable that some the efficient, highly adaptable, warm - blooded mammals that evolved on land should have returned to the sea. Those that did have flourished Within about 50 million years - no time at all, geologically speaking - one of the four kinds of mammals that has returned to a marine environment has developed into the largest of all animal forms, the whale. A second kind, the seal, has produced what is probably the greatest population of large carnivorous mammals on Earth. This suggests that these "top dogs" of the ocean are prospering and multiplying. However, such has not been the case, at least not for the last 150 years. Trouble has closed in or these mammals in the form of equally warm-blooded and even more efficient and adaptable predators, humans. At sea, as on land, humans have now positioned themselves on to -of the whole great pyramid of life, and they have caused serious problems for the mammals of the sea.

 

          There is a simple reason for this. Marine mammals have the misfortune to be swimming aggregates of commodities that humans want: fur, oil, and meat. Even so, they might not be so vulnerable to human depredation if they did not, like humans, reproduce so slowly. Every year humans take more than 50 million tons of fish from the oceans without critically depleting the population of any species. But the slow-breeding mammals of the sea have been all but wiped out by humans seeking to satisfy their wants and whims.

It can be inferred from the passage that marine mammals are like humans in which of the following ways".

• They survive despite changes in their metabolic rates.

• They reproduce slowly.

• They are prospering and multiplying.

• They are depleting the vegetation of the seas.

          In general, as soon as the newborn child's muscles, sense organs, and nerves are fully formed, the child begins to use them. But much of the human nervous system is not fully developed until the child is a year or two old, and some parts, such as the corpus callosum, continue to mature for at least the next 20 years.

 

          The general pattern of bodily development is from head to foot. Simple skills, such as head movements, appear first because the structures that control these skills are among the first to mature. More complex behavior patterns, such as crawling, standing, and walking, come much later in the developmental sequence than head movements do.

 

          The motor centers in the brain are connected by long nerve fibers(usually through one or more synapses) to the muscles in various parts of the body. Since the head muscles are closer to the brain than are the foot muscles, according to one theory, the head comes under the control of the motor centers long before the feet do. The appearance of a new motor skill (such as crawling and grasping) always suggests that a new part of the child's body has just matured-that is, that the brain centers have just begun to control the muscles involved in the new motor skill.

What is the author's main purpose in this passage?

• To describe how children crawl, stand, and walk

• To explain why some children are slow to develop

• To describe early physical development in children

• To explain the function of the corpus callosum

          In general, as soon as the newborn child's muscles, sense organs, and nerves are fully formed, the child begins to use them. But much of the human nervous system is not fully developed until the child is a year or two old, and some parts, such as the corpus callosum, continue to mature for at least the next 20 years.

 

          The general pattern of bodily development is from head to foot. Simple skills, such as head movements, appear first because the structures that control these skills are among the first to mature. More complex behavior patterns, such as crawling, standing, and walking, come much later in the developmental sequence than head movements do.

 

          The motor centers in the brain are connected by long nerve fibers(usually through one or more synapses) to the muscles in various parts of the body. Since the head muscles are closer to the brain than are the foot muscles, according to one theory, the head comes under the control of the motor centers long before the feet do. The appearance of a new motor skill (such as crawling and grasping) always suggests that a new part of the child's body has just matured-that is, that the brain centers have just begun to control the muscles involved in the new motor skill.

According to the passage, the corpus callosum is part of the human....

• muscular system

• digestive system

• circulatory system

• nervous system

          In general, as soon as the newborn child's muscles, sense organs, and nerves are fully formed, the child begins to use them. But much of the human nervous system is not fully developed until the child is a year or two old, and some parts, such as the corpus callosum, continue to mature for at least the next 20 years.

 

          The general pattern of bodily development is from head to foot. Simple skills, such as head movements, appear first because the structures that control these skills are among the first to mature. More complex behavior patterns, such as crawling, standing, and walking, come much later in the developmental sequence than head movements do.

 

          The motor centers in the brain are connected by long nerve fibers(usually through one or more synapses) to the muscles in various parts of the body. Since the head muscles are closer to the brain than are the foot muscles, according to one theory, the head comes under the control of the motor centers long before the feet do. The appearance of a new motor skill (such as crawling and grasping) always suggests that a new part of the child's body has just matured-that is, that the brain centers have just begun to control the muscles involved in the new motor skill.

According to the passage, which of the following motor skills does an infant first develop?

• Moving the head

• Crawling

• Controlling the arms     

• Kicking

          In general, as soon as the newborn child's muscles, sense organs, and nerves are fully formed, the child begins to use them. But much of the human nervous system is not fully developed until the child is a year or two old, and some parts, such as the corpus callosum, continue to mature for at least the next 20 years.

 

          The general pattern of bodily development is from head to foot. Simple skills, such as head movements, appear first because the structures that control these skills are among the first to mature. More complex behavior patterns, such as crawling, standing, and walking, come much later in the developmental sequence than head movements do.

 

          The motor centers in the brain are connected by long nerve fibers(usually through one or more synapses) to the muscles in various parts of the body. Since the head muscles are closer to the brain than are the foot muscles, according to one theory, the head comes under the control of the motor centers long before the feet do. The appearance of a new motor skill (such as crawling and grasping) always suggests that a new part of the child's body has just matured-that is, that the brain centers have just begun to control the muscles involved in the new motor skill.

According to the passage, we can tell that the child's brain centers have begun to control new muscles when

• the child's brain matures

• the child moves its body in new ways

• long nerve fibers disappear

• the child performs an acquired skill more rapidly