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 question from 18 to 25.
The principle of use and disuse states that those parts of organisms' bodies that are used grown larger. Those parts that are not tend to wither away. It is an observed fact that when you exercise particular muscles, they grow. Those that are never used dimish. By examining a man's body, we can tell which muscles he uses and which he doesn't. We may even be able to guess his profession or his reaction. Enthusiasts of the "body- building" cult make use of the principle of use and disuse to "build" their bodies, almost like a piece of sculpture, into whatever unnatural shape is demanded by fashion in this peculiar minority culture. Muscles are not the only parts of the body that respond to use in this kind of way. Walk barefoot and you acquire harder skin on your soles. It is easy to tell a farmer from a bank teller by looking at their hands alone. The farmer's hands are horny, hardened by long exposure to rough work. The teller’s hands are relatively soft.
The principle of use and disuse enables animals to become better at the job of surviving in their world, progressively better during their lifetime as a result of living in that world. Humans, through direct exposure to sunlight, or lack of it, develop a skin color which equips them better to survive in the particular local conditions.
Too much sunlight is dangerous. Enthusiastic sunbathers with very fair skins are susceptible to skin cancer. Too little sunlight, on the other hand, leads to vitamin-D deficiency and rickets. The brown pigment melanin which is synthesized under the influence of sunlight, makes a screen to protect the underlying tissues from the harmful effects of further sunlight. If a suntanned person moves to a less sunny climate, the melanin disappears, and the body is able to benefit from what little sun there is. This can be represented as an instance of the principle of use and disuse: skin goes brown when it is "used", and fades to white when it is not.
In the second paragraph, the author mentions sun tanning as an example of _______
A. humans improving their local condition
B. humans surviving in adverse conditions
C. humans using the principle of use and disuse
D. humans running the risk of skin cancer
Đáp án C.
Key word: sun tanning, example of
Clue: “The principle of use and disuse enables animals to become better at the job of surviving in their world, progressively better during their lifetime as a result of living in that world. Humans, through direct exposure to sunlight, or lack of it, develop a skin color which equips them better to survive in the particular local conditions. Too much sunlight is dangerous”: Nguyên lí của việc dùng hay không dùng cho phép động vật trở nên tốt hơn trong việc tồn tại trong môi trường chúng sống, càng ngày càng tốt lên trong suốt cuộc đời của chúng như một kết quả của việc sống trong đó. Con người tiếp xúc trực tiếp với ánh nắng mặt trời hay thiếu ánh nắng đều phát triển một màu da để tồn tại tốt hơn trong môi trường địa phương đặc biệt.
Phân tích đáp án:
A. Humans improving their local condition: Con người cải thiện điều kiện ở địa phương của họ
B. Humans surviving in adverse conditions: Con người sống sót trong điều kiện bất lợi.
C. Humans using the principle of use and disuse: Con người sử dụng nguyên tắc sử dụng và không sử dụng.
D. Humans running the risk of skin cancer: Con người có nguy cơ ung thư da.
Trong clue ta thấy câu trước nói về quy luật sử dụng hay không sử dụng “ánh nắng” của con người nên câu sau phải là ví dụ cho việc này. Đáp án chính xác là C.