Although the prevailing supposition has been that it is too hot for microorganis

游客2024-01-13  20

问题 Although the prevailing supposition has been that it is too hot for microorganisms to survive deep below the Earth’ s surface, some scientists argue that there are living communities of microorganisms there that have been cut off from surface life for millions of years. These scientists base their argument on the discovery of living microorganisms in samples of material that were taken from holes drilled as deep as 1.74 miles. The scientists’ argument depends on which of the following assumptions?

选项 A、The microorganisms brought up were of a species that is related to those previously known to science.
B、No holes have been drilled into the Earth’ s surface to a distance deeper than 1. 74 miles.
C、The microorganisms did not come from surface soil that came into contact with the drilling equipment.
D、The stratum from which the samples came has been below the surface of the Earth ever since the Earth came into existence.
E、The temperature at the bottom of the holes drilled was not significantly hotter than that of the hottest spots on the Earth’s surface.

答案 C

解析 本题根据从地表以下1.74英里深的地方取得的样品中存在活着的微生物,得出了在地层深处存在活着的微生物的结论,属于典型的“B,A”模式。要想使本题的结论成立,就必须寻找一个原因来解释或加强样品确实取自地层深处,即排除他因。由此分析可知(C)为正确答案;(E)是较易误选的选项,从表面上看它似乎能对普遍的猜想构成反对,从而对本题的结论构成支持。但是要知道,地表以下温度太高是一个既定的事实,那些科学家的实验只是为了证实地层深处存在微生物的可能性,而不是要证实微生物一定要在和地面表层温度相一致的温度区间内才能存活,因此(E)为错误选项。
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