Read the following passage and mark the letter A, B, C, or D on your answer sheet to Indicate the correct answer to each of the questions.

There is a wide range of organisms by their population whose lives mostly depend on how they hunt or are hunted. And most living organisms have some way of protecting themselves from natural predators. Some mammals, like the platypus, carry internal toxins to transmit to predators via biting or other means, and some plants protect themselves by being poisonous. The African crested rat was originally thought to be poisonous because predators that tried to eat it often became paralyzed. But scientists have recently learned that's not actually the case.

 The crested rat chews on the poisonous bark of a certain tree, and then smears the chewed-up substance onto its fur, where a strip of special quill-like hairs soaks up the poisonous mixture. Though similar to a porcupine's, the quills do differ: whereas the porcupine defends itself by poking predators, the African rat uses its quill-like hairs to deliver poison to them. When a predator comes after it, instead of running away, the rat stays put and parts its hair to reveal the strip of fur on its back where the poison is being stored. That raised strip is the first thing that receives a bite, and the poison inside disables the predator. These hair tubes are unusual. In fact, scientists do not know of another animal that uses plant poison in this way.

Scientists are puzzled that the rat doesn't appear to be affected by the poison. Because it affects heartbeat regulation, understanding how the rat can keep its heart rate regulated effectively while using the poison could help scientists develop new medicines for people with heart trouble. And they hope that those suffering from heart diseases will benefit from this.

The word “paralyzed” in paragraph 1 is closest in meaning to

A. disabled

B. unaffected

C. inaccessible

D. undecided

Read the following passage and mark the letter A, B, C, or D on your answer sheet to Indicate the correct answer to each of the questions.

There is a wide range of organisms by their population whose lives mostly depend on how they hunt or are hunted. And most living organisms have some way of protecting themselves from natural predators. Some mammals, like the platypus, carry internal toxins to transmit to predators via biting or other means, and some plants protect themselves by being poisonous. The African crested rat was originally thought to be poisonous because predators that tried to eat it often became paralyzed. But scientists have recently learned that's not actually the case.

 The crested rat chews on the poisonous bark of a certain tree, and then smears the chewed-up substance onto its fur, where a strip of special quill-like hairs soaks up the poisonous mixture. Though similar to a porcupine's, the quills do differ: whereas the porcupine defends itself by poking predators, the African rat uses its quill-like hairs to deliver poison to them. When a predator comes after it, instead of running away, the rat stays put and parts its hair to reveal the strip of fur on its back where the poison is being stored. That raised strip is the first thing that receives a bite, and the poison inside disables the predator. These hair tubes are unusual. In fact, scientists do not know of another animal that uses plant poison in this way.

Scientists are puzzled that the rat doesn't appear to be affected by the poison. Because it affects heartbeat regulation, understanding how the rat can keep its heart rate regulated effectively while using the poison could help scientists develop new medicines for people with heart trouble. And they hope that those suffering from heart diseases will benefit from this.

In paragraph 2, what does the word “them” refer to?

A. predators

B. porcupines

C. crested rats

D. quill-like hairs

Read the following passage and mark the letter A, B, C, or D on your answer sheet to Indicate the correct answer to each of the questions.

There is a wide range of organisms by their population whose lives mostly depend on how they hunt or are hunted. And most living organisms have some way of protecting themselves from natural predators. Some mammals, like the platypus, carry internal toxins to transmit to predators via biting or other means, and some plants protect themselves by being poisonous. The African crested rat was originally thought to be poisonous because predators that tried to eat it often became paralyzed. But scientists have recently learned that's not actually the case.

 The crested rat chews on the poisonous bark of a certain tree, and then smears the chewed-up substance onto its fur, where a strip of special quill-like hairs soaks up the poisonous mixture. Though similar to a porcupine's, the quills do differ: whereas the porcupine defends itself by poking predators, the African rat uses its quill-like hairs to deliver poison to them. When a predator comes after it, instead of running away, the rat stays put and parts its hair to reveal the strip of fur on its back where the poison is being stored. That raised strip is the first thing that receives a bite, and the poison inside disables the predator. These hair tubes are unusual. In fact, scientists do not know of another animal that uses plant poison in this way.

Scientists are puzzled that the rat doesn't appear to be affected by the poison. Because it affects heartbeat regulation, understanding how the rat can keep its heart rate regulated effectively while using the poison could help scientists develop new medicines for people with heart trouble. And they hope that those suffering from heart diseases will benefit from this.

The word “defends” in paragraph 2 is closest in meaning to

A. encourages

B. protects

C. feeds

D. pretends

Read the following passage and mark the letter A, B, C, or D on your answer sheet to Indicate the correct answer to each of the questions.

There is a wide range of organisms by their population whose lives mostly depend on how they hunt or are hunted. And most living organisms have some way of protecting themselves from natural predators. Some mammals, like the platypus, carry internal toxins to transmit to predators via biting or other means, and some plants protect themselves by being poisonous. The African crested rat was originally thought to be poisonous because predators that tried to eat it often became paralyzed. But scientists have recently learned that's not actually the case.

 The crested rat chews on the poisonous bark of a certain tree, and then smears the chewed-up substance onto its fur, where a strip of special quill-like hairs soaks up the poisonous mixture. Though similar to a porcupine's, the quills do differ: whereas the porcupine defends itself by poking predators, the African rat uses its quill-like hairs to deliver poison to them. When a predator comes after it, instead of running away, the rat stays put and parts its hair to reveal the strip of fur on its back where the poison is being stored. That raised strip is the first thing that receives a bite, and the poison inside disables the predator. These hair tubes are unusual. In fact, scientists do not know of another animal that uses plant poison in this way.

Scientists are puzzled that the rat doesn't appear to be affected by the poison. Because it affects heartbeat regulation, understanding how the rat can keep its heart rate regulated effectively while using the poison could help scientists develop new medicines for people with heart trouble. And they hope that those suffering from heart diseases will benefit from this.

What would scientists like to investigate further?

A. Medicine used to counteract poison.

B. Other animals like the crested rat.

C. Health effects of a chemical.

D. Rats with unhealthy hearts.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to Indicate the correct answer to each of the questions.

There is a wide range of organisms by their population whose lives mostly depend on how they hunt or are hunted. And most living organisms have some way of protecting themselves from natural predators. Some mammals, like the platypus, carry internal toxins to transmit to predators via biting or other means, and some plants protect themselves by being poisonous. The African crested rat was originally thought to be poisonous because predators that tried to eat it often became paralyzed. But scientists have recently learned that's not actually the case.

 The crested rat chews on the poisonous bark of a certain tree, and then smears the chewed-up substance onto its fur, where a strip of special quill-like hairs soaks up the poisonous mixture. Though similar to a porcupine's, the quills do differ: whereas the porcupine defends itself by poking predators, the African rat uses its quill-like hairs to deliver poison to them. When a predator comes after it, instead of running away, the rat stays put and parts its hair to reveal the strip of fur on its back where the poison is being stored. That raised strip is the first thing that receives a bite, and the poison inside disables the predator. These hair tubes are unusual. In fact, scientists do not know of another animal that uses plant poison in this way.

Scientists are puzzled that the rat doesn't appear to be affected by the poison. Because it affects heartbeat regulation, understanding how the rat can keep its heart rate regulated effectively while using the poison could help scientists develop new medicines for people with heart trouble. And they hope that those suffering from heart diseases will benefit from this.

What are scientists surprised by?

A. How toxic plant poison can be.

B. How useful plant toxins can be.

C. How quickly rats learn new behavior.

D. That the rats are protected from the poison.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to Indicate the correct answer to each of the questions.

There is a wide range of organisms by their population whose lives mostly depend on how they hunt or are hunted. And most living organisms have some way of protecting themselves from natural predators. Some mammals, like the platypus, carry internal toxins to transmit to predators via biting or other means, and some plants protect themselves by being poisonous. The African crested rat was originally thought to be poisonous because predators that tried to eat it often became paralyzed. But scientists have recently learned that's not actually the case.

 The crested rat chews on the poisonous bark of a certain tree, and then smears the chewed-up substance onto its fur, where a strip of special quill-like hairs soaks up the poisonous mixture. Though similar to a porcupine's, the quills do differ: whereas the porcupine defends itself by poking predators, the African rat uses its quill-like hairs to deliver poison to them. When a predator comes after it, instead of running away, the rat stays put and parts its hair to reveal the strip of fur on its back where the poison is being stored. That raised strip is the first thing that receives a bite, and the poison inside disables the predator. These hair tubes are unusual. In fact, scientists do not know of another animal that uses plant poison in this way.

Scientists are puzzled that the rat doesn't appear to be affected by the poison. Because it affects heartbeat regulation, understanding how the rat can keep its heart rate regulated effectively while using the poison could help scientists develop new medicines for people with heart trouble. And they hope that those suffering from heart diseases will benefit from this.

In paragraph 1, why does the author mention the platypus?

A. To illustrate that mammals may eat poisonous plants.

B. To give an example of a mammal that uses poison.

C. To show how it differs from the crested rat.

D. To explain that the platypus is at risk.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to Indicate the correct answer to each of the questions.

There is a wide range of organisms by their population whose lives mostly depend on how they hunt or are hunted. And most living organisms have some way of protecting themselves from natural predators. Some mammals, like the platypus, carry internal toxins to transmit to predators via biting or other means, and some plants protect themselves by being poisonous. The African crested rat was originally thought to be poisonous because predators that tried to eat it often became paralyzed. But scientists have recently learned that's not actually the case.

 The crested rat chews on the poisonous bark of a certain tree, and then smears the chewed-up substance onto its fur, where a strip of special quill-like hairs soaks up the poisonous mixture. Though similar to a porcupine's, the quills do differ: whereas the porcupine defends itself by poking predators, the African rat uses its quill-like hairs to deliver poison to them. When a predator comes after it, instead of running away, the rat stays put and parts its hair to reveal the strip of fur on its back where the poison is being stored. That raised strip is the first thing that receives a bite, and the poison inside disables the predator. These hair tubes are unusual. In fact, scientists do not know of another animal that uses plant poison in this way.

Scientists are puzzled that the rat doesn't appear to be affected by the poison. Because it affects heartbeat regulation, understanding how the rat can keep its heart rate regulated effectively while using the poison could help scientists develop new medicines for people with heart trouble. And they hope that those suffering from heart diseases will benefit from this.

What is the main purpose of the passage?

A. To show how animals can affect plant life.

B. To compare one animal to other similar ones.

C. To emphasize the dangers of researching animals.

D. To discuss an unusual animal defense technique.

1. affect         aquatic      contaminate     permanent               6.  Billboard         litter        pollution    visual

2. litter           official       visual               icon                         7.  Poison            thermal   effect          victim

3. sure            measure     pleasure          treasure                     8. Homeless       typhoon  volcanic     disaster

4. radiation   collapse     parade             volcano                     9. Untreated    channel    discover    parade 

5. legend       engine       language          underground                        10. Planet        fainted    outbreak     radiation