新东方逻辑题

随便翻了一下,有几道题有疑问.请大家帮忙解释一下.

when amphibians first appeared on Earth millions of years ago,the amount of ultraviolet radiation penetrating Earth's atmosphere was much greater than it is today.Therefore,current dramatic increases in amphibian populations cannot be the result of recent increases in ultraviolet radiation penetrating Earth's atmosphere.

which is an assumption on which the argument depends?

A the eggs of modern amphibians are not significantly more vulnerable to ultraviolet radiation than the eggs of the first amphibians were.

B Modern amphibians are not as likely as the first amphibians were to live in habitats that shield them from ultraviolet radiation.

C Populations of modern amphibians are not able to adapt to changing levels of radiation as readily as populations of early amphibians were.

D The skin of amphibians is greatly more sensitive to ultraviolet radiation than the skin of other animals is .

E the skin of amphibians is less sensitive to ultraviolet radiation than to other types of radiation.

请大家对给出的答案分析一下.谢了先

当两栖动物几百万年前首次出现在地球上时，穿透地球大气的紫外线比现在更强。因此，现在两栖动物数量的大量增加不是最近穿透大气紫外线增强的结果。

含义：两栖动物出现时紫外线更强，之后的紫外线是逐渐变弱的，但是两栖动物的数量却是增加的，即两栖动物的增加是伴随着紫外线变弱的。所以得出结论，近期两栖动物的增加不是紫外线增强的结果。

选出假设选项。

b现代两栖动物不像最早的两栖动物住在可以遮蔽紫外线的地方（现代的两栖动物害怕强紫外线）

c现代两栖动物不能像最早的两栖动物那样快速适应紫外线程度的改变（现代的两栖动物害怕紫外线的强弱变化）

my answer: C