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Câu hỏi: 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 from 35 to 42
All living cells in an animal's body require energy to power the various chemical processes going in inside them. This energy is ultimately supplied by the food that animals eat. These chemical processes are collectively referred to as metabolism, and one of the byproducts of metabolism is heat. Metabolic rates vary significantly between species. Warm-blooded animals (birds and mammals) have metabolic rates about five to ten times higher than those of similarly sized cold-blooded ones (reptiles, amphibians, and fishes). And it is precisely because birds and mammals have such high metabolic rates that they are able to keep their bodies warm.
The terms warm-blooded and cold-blooded are still in everyday use, but they are not entirely precise. Anyone who has handled a snake knows this because a snake's body actually feels quite warm. But very little of the snake's body heat originates internally, from its cells, most of it having been supplied from the outside, either by the sun or by a heat lamp. Instead of referring to reptiles as cold-blooded, they are best described as ectothermic, meaning "outside heat". Similarly, birds and mammals are said to be endothermic, meaning "inside heat".
There are advantages and disadvantages to each thermal strategy. Reptiles are usually sluggish first thing in the morning, their body temperatures having dropped during the cool of the night. Accordingly, they have to bask in the sun to raise their body temperatures, but once they have warmed up sufficiently, they can go about their business. By altering between the sun when they are too cool, and the shade when they are too warm, many reptiles are able to maintain their body temperatures at optimum levels of about 95°F or more. Endotherms, on the other hand, maintain temperatures of about 98°F all the time, so they are always ready for action.
I used to keep a crocodile. He had very sharp teeth, and I had to be careful how I handled him during the daytime, when he was warm. But I could do whatever I wanted at night, when he was cold, without any fear of being bitten. The obvious disadvantage of being ectothermic is that the animal"s activity levels are dependent upon the environment. But its low metabolic rates mean that it requires far less food, which is an advantage. I used to feed the crocodile a tiny piece of liver once a week, while the family cat demanded three meals every day. We should therefore not think that reptiles are inferior to mammals and birds; they are just different.
A. Because he wants to advise on how to handle pets safely.
B. Because he wants to say that keeping a reptile as pet is less expensive.
C. Because he wants to compare reptiles" metabolic rates with those of mammals and birds.
D. Because he wants to illustrate that ectothermism has both advantages and disadvantages.
All living cells in an animal's body require energy to power the various chemical processes going in inside them. This energy is ultimately supplied by the food that animals eat. These chemical processes are collectively referred to as metabolism, and one of the byproducts of metabolism is heat. Metabolic rates vary significantly between species. Warm-blooded animals (birds and mammals) have metabolic rates about five to ten times higher than those of similarly sized cold-blooded ones (reptiles, amphibians, and fishes). And it is precisely because birds and mammals have such high metabolic rates that they are able to keep their bodies warm.
The terms warm-blooded and cold-blooded are still in everyday use, but they are not entirely precise. Anyone who has handled a snake knows this because a snake's body actually feels quite warm. But very little of the snake's body heat originates internally, from its cells, most of it having been supplied from the outside, either by the sun or by a heat lamp. Instead of referring to reptiles as cold-blooded, they are best described as ectothermic, meaning "outside heat". Similarly, birds and mammals are said to be endothermic, meaning "inside heat".
There are advantages and disadvantages to each thermal strategy. Reptiles are usually sluggish first thing in the morning, their body temperatures having dropped during the cool of the night. Accordingly, they have to bask in the sun to raise their body temperatures, but once they have warmed up sufficiently, they can go about their business. By altering between the sun when they are too cool, and the shade when they are too warm, many reptiles are able to maintain their body temperatures at optimum levels of about 95°F or more. Endotherms, on the other hand, maintain temperatures of about 98°F all the time, so they are always ready for action.
I used to keep a crocodile. He had very sharp teeth, and I had to be careful how I handled him during the daytime, when he was warm. But I could do whatever I wanted at night, when he was cold, without any fear of being bitten. The obvious disadvantage of being ectothermic is that the animal"s activity levels are dependent upon the environment. But its low metabolic rates mean that it requires far less food, which is an advantage. I used to feed the crocodile a tiny piece of liver once a week, while the family cat demanded three meals every day. We should therefore not think that reptiles are inferior to mammals and birds; they are just different.
(Adapted from Reading TOEFL Practice)
Why does the author mention his pet in the last paragraph?A. Because he wants to advise on how to handle pets safely.
B. Because he wants to say that keeping a reptile as pet is less expensive.
C. Because he wants to compare reptiles" metabolic rates with those of mammals and birds.
D. Because he wants to illustrate that ectothermism has both advantages and disadvantages.
Tại sao tác giả đề cập đến thú cưng của mình trong đoạn cuối?
A. Bởi vì ông ấy muốn tư vấn về cách chăm sóc thú cưng an toàn.
B. Bởi vì ông ấy muốn nói rằng giữ một loài bò sát làm thú cưng ít tốn kém hơn.
C. Bởi vì ông ta muốn so sánh tốc độ trao đổi chất của các loài bò sát với các loài động vật có vú và chim.
D. Bởi vì ông ta muốn minh họa rằng việc biến nhiệt có cả ưu điểm và nhược điểm.
Ở đoạn cuối, tác giả đưa ra thông tin về con cá sấu tác giả nuôi và nói rằng:
The obvious disadvantage of being ectothermic is that the animal's activity levels are dependent upon the environment. But its low metabolic rates mean that it requires far less food, which is an advantage.
Nhược điểm rõ ràng của việc biến nhiệt là mức độ hoạt động của động vật phụ thuộc vào môi trường. Nhưng tỷ lệ trao đổi chất thấp của nó có nghĩa là nó đòi hỏi thực phẩm ít hơn nhiều, đó là một lợi thế. => Do đó, mục đích của tác giả là nói về ưu và nhược điểm của động vật biến nhiệt.
A. Bởi vì ông ấy muốn tư vấn về cách chăm sóc thú cưng an toàn.
B. Bởi vì ông ấy muốn nói rằng giữ một loài bò sát làm thú cưng ít tốn kém hơn.
C. Bởi vì ông ta muốn so sánh tốc độ trao đổi chất của các loài bò sát với các loài động vật có vú và chim.
D. Bởi vì ông ta muốn minh họa rằng việc biến nhiệt có cả ưu điểm và nhược điểm.
Ở đoạn cuối, tác giả đưa ra thông tin về con cá sấu tác giả nuôi và nói rằng:
The obvious disadvantage of being ectothermic is that the animal's activity levels are dependent upon the environment. But its low metabolic rates mean that it requires far less food, which is an advantage.
Nhược điểm rõ ràng của việc biến nhiệt là mức độ hoạt động của động vật phụ thuộc vào môi trường. Nhưng tỷ lệ trao đổi chất thấp của nó có nghĩa là nó đòi hỏi thực phẩm ít hơn nhiều, đó là một lợi thế. => Do đó, mục đích của tác giả là nói về ưu và nhược điểm của động vật biến nhiệt.
Đáp án D.