THE PRINCIPLE OF USE AND DISUSE STATES THAT THOSE PARTS OF ORGANISMS’ DỊCH

     

The principle of use and disuse states that those parts of organisms" bodies that are used grown larger. Those parts that are not tend khổng lồ wither away. It is an observed fact that when you exercise particular muscles, they grow. Those that are never used diminish. By examining a man"s body, we can tell which muscles he uses và which he does not. We may even be able to lớn guess his profession or his recreation. Enthusiasts of the ‘body- building’ cult make use of the principle of use và disuse to lớn 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 toàn thân that respond to lớn 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 ngân hàng teller by looking at their hands alone. The farmer"s hands are horny, hardened by long exposure lớn rough work. The teller"s hands are relatively soft. The principle of use và 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 màu sắc which equips them better lớn 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 lớn vitamin-D deficiency and rickets. The brown pigment melanin which is synthesized under the influence of sunlight, makes a screen to lớn protect the underlying tissues from the harmful effects of further sunlight. If a suntanned person moves khổng lồ a less sunny climate, the melanin disappears, and the body is able to lớn benefit from what little sun there is. This can be represented as an instance of the principle of use & disuse: skin goes brown when it is used, & fades to lớn white when it is not.

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A. How principles of use & disuse change people"s concepts of themselves.

B. The way in which people change themselves lớn conform lớn fashion.

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C. The changes that occur according khổng lồ the principle of use and disuse.

D.

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The effects of the sun on the principle of use & disuse.


Đáp án C

Câu đầu bài bác nêu rõ nội dung đa phần được đề cập cho trong toànđoạn văn: “ The principle of use and disuse states that those parts of organisms" bodies that are used grown larger. Those parts that are not tend lớn wither away