6.1 Central Idea

Which statement best describes the central idea of the passage?

• Octopuses are curious creatures.

• Octopuses have relatively large brains.

• Octopuses in captivity can cause problems.

• Octopuses are surprisingly intelligent creatures.

 In 1902, a young boy named Albert discovered that shaking a jar of honey would always attract bees to its lid. Scientists later confirmed that bees can detect vibrations as well as scents. A bee’s brain, though tiny, can remember routes, recognize patterns, and even communicate through a "waggle dance." This special dance helps bees tell one another where flowers can be found. Bees may be small, but their abilities are extraordinary.

Question: Which statement best describes the central idea of the passage?

• Bees only care about honey.

• Bees use a special dance to find flowers.

• Bees are more intelligent than their size suggests.

• Bees can detect vibrations.

 In the 1960s, researchers discovered that dolphins could understand symbols on a keyboard to request toys and food. These marine mammals are known for their playful behavior and cooperation in groups. They can even recognize themselves in mirrors, which very few animals can do. Dolphins communicate with whistles and clicks, proving that their world is full of intelligence and complexity.

Question: Which statement best describes the central idea of the passage?

• Dolphins are playful animals.

• Dolphins can communicate in complex ways.

• Dolphins can recognize themselves in mirrors.

• Dolphins are highly intelligent creatures.

In the early 1900s, scientists were surprised to find that crows used sticks to pull insects out of holes. Later studies showed that crows can bend wires into hooks to retrieve food. These birds can solve puzzles, recognize human faces, and even drop nuts onto roads so cars can crack them open. With their sharp problem-solving skills, crows prove that bird brains are anything but simple.

Question: Which statement best describes the central idea of the passage?

• Crows are good at recognizing faces.

• Crows can use tools to solve problems.

• Crows are clever and resourceful creatures.

• Crows often drop nuts onto roads.

In the 1800s, a horse named Clever Hans amazed crowds by tapping his hoof to solve math problems. For a long time, people believed Hans could actually count. Later, scientists discovered that Hans was responding to tiny facial cues from his trainer. Even though he wasn’t truly solving math, this case taught scientists important lessons about how animals notice details humans may overlook.

Question: Which statement best describes the central idea of the passage?

• Horses can solve math problems.

• Clever Hans tricked scientists.

• Animals can notice subtle human signals.

• Clever Hans amazed crowds with his tricks.

Penguins may look clumsy on land, but in the water, they are expert swimmers. Using their wings like flippers, they can reach speeds of up to 15 miles per hour. Penguins can also dive deep to catch fish and are excellent at conserving oxygen while underwater. Though they cannot fly in the air, their powerful swimming skills make them masters of the ocean.

Question: Which statement best describes the central idea of the passage?

• Penguins cannot fly in the air.

• Penguins are clumsy on land.

• Penguins are skilled and powerful swimmers.

• Penguins dive deep to catch fish.

In 1914, a Canadian farmer noticed one of his cats opening a door by turning the handle with her paw. Cats are curious creatures, often figuring out ways to get into cupboards, boxes, or even locked rooms. Studies show that cats remember solutions to problems for months. They also learn by watching humans and other cats, proving they are both observant and persistent.

Question: Which statement best describes the central idea of the passage?

• Cats can open doors.

• Cats are curious and intelligent animals.

• Cats learn by watching humans.

• Cats remember problem solutions for months.

In 1957, scientists studying chimpanzees were astonished when one used a blade of grass to fish termites out of a mound. Later, researchers saw chimps shaping sticks and even using stones as hammers to crack nuts. Chimpanzees also share food, show emotions, and form complex social groups. These skills show that humans share much in common with our closest animal relatives.

Question: Which statement best describes the central idea of the passage?

• Chimpanzees live in groups.

• Chimpanzees use tools to solve problems.

• Chimpanzees are emotional animals.

• Chimpanzees share many traits with humans.

 In the deserts of North Africa, fennec foxes survive extreme heat with their enormous ears. These ears release body heat and also allow the foxes to hear prey moving underground. Fennec foxes rest during the day and hunt at night, which helps them avoid the harsh sun. Small but clever, they are perfectly adapted to their dry, desert home.

Question: Which statement best describes the central idea of the passage?

• Fennec foxes have large ears.

• Fennec foxes avoid the sun by resting.

• Fennec foxes are well adapted to desert life.

• Fennec foxes hunt at night.

 In 2009, researchers discovered that elephants could recognize themselves in mirrors, touching marks on their heads that they could only see in the reflection. Elephants also mourn their dead, protect their young, and work together to find food and water. These behaviors reveal that elephants are highly social animals with remarkable intelligence and empathy.

Question: Which statement best describes the central idea of the passage?

• Elephants can recognize themselves in mirrors.

• Elephants mourn their dead.

• Elephants are highly intelligent and empathetic creatures.

• Elephants work together to find food and water.