FeiFei-38

38. Amphibian populations are declining in numbers worldwide. Not coincidentally, the earth’s ozone layer has been continuously depleted throughout the last 50 years. Atmospheric ozone blocks UV-B, a type of ultraviolet radiation that is continuously produced by the sun, and which can damage genes. Because amphibians lack hair, hide, or feathers to shield them, they are particularly vulnerable to UV-B radiation. In addition, their gelatinous eggs lack the protection of leathery or hard shells. Thus, the primary cause of the declining amphibian population is the depletion of the ozone layer.

Each of the following, if true, would strengthen the argument EXCEPT:

A.        Of the various types of radiation blocked by atmospheric ozone, UV-B is the only type that can damage genes.

B.        Amphibian populations are declining far more rapidly than are the populations of non-amphibian species whose tissues and eggs have more natural protection from UV-B.

C.        Atmospheric ozone has been significantly depleted above all the areas of the world in which amphibian populations are declining.

D.       The natural habitat of amphibians has not become smaller over the past century.

E.        Amphibian populations have declined continuously for the last 50 years.

以下是狒狒逻辑宝典详解版的解释：

答案：D

思路：原文论述臭氧层的破坏造成UV-B辐射过量是导致两栖动物数量减少的主要原因。

A：支持说明为什么是UV-B而不是其他原因。

B：支持说明为什么UV-B会降低两栖动物的数量。

C：提供空间论据说明臭氧层受损和两栖动物数量减少的相关性。

D：中性评价。不Weaken也不Strengthen.

E：提供时间论据说明臭氧层受损和两栖动物数量减少的相关性。

可是题目版的答案是A。

究竟哪个是正确答案？

请NN给指点一下？

A强调UVB是破坏基因的唯一因素,这无法影响结论.因为假如令A取否,即它不是唯一因素,这也无法影响结论.也就是说A是无关的.

而D暗示,两栖动物生存的地区没有缩小,也就是说主要因素在于臭氧层受损.显然有利于加强结论

而如果令D取否,两栖动物生存的地区缩小了,那就暗示了主要因素可能是生存的地区缩小了,削弱了结论

顶

A是无关的，因为结论说数量的下降是因为臭氧层被破坏，这和是不是UV-B，UV-C，或是任何其他臭氧层可以隔离的紫外线造成的没有任何关系。总之只要加强是臭氧层破坏造成了数量下降这个结论就可以了，至于臭氧层隔离的是哪一个，而哪一个能伤害基因，没有关系。

但是我觉得D也有些牵强。居住地缩小了就会减少数量吗，似乎需要common sense来做题哦。

应该是A，D是排除他因加强！