标题: 实在想不通的一道题 [打印本页] 作者: GabrielHong 时间: 2010-8-4 15:59 标题: 实在想不通的一道题 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 nonamphibian 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. 答案是A。实在是想不通A选项为什么会不加强。作者: 夏日飘雪 时间: 2010-8-4 17:14
这题难道不是选D吗。。。作者: cooldavy 时间: 2010-8-4 18:52
貌似只能选A……因为选项里说只有UV-B damage genes，并不是说会危害A生物的生存的辐射只有UV-B，可能还有其他辐射也会危害A生物，有点像削弱项作者: fly12404 时间: 2010-8-4 18:59
題目是說A的減少是因為ozone layer的減少 所以不管只有一種輻射 或兩種 或三種以上 A的減少都還是因為ozone layer