101.
Biological functions of many plants and animals vary in cycles that are repeated every 24 hours. It is tempting to suppose that alteration in the intensity of incident light is the stimulus that controls these daily biological rhythms. But there is much evidence to contradict this hypothesis. Which of the following, if known, is evidence that contradicts the hypothesis stated in lines 2-5 above? (A) Human body temperature varies throughout the day, with the maximum occurring in the late afternoon and the minimum in the morning. (B) While some animals, such as the robin, are more active during the day, others, such as mice, show greater activity at night. (C) When people move from one time zone to another, their daily biological rhythms adjust in a matter of days to the periods of sunlight and darkness in the new zone. (D) Certain single-cell plants display daily biological rhythms even when the part of the cell containing the nucleus is removed. (E) Even when exposed to constant light intensity around the clock, some algae display rates of photosynthesis that are much greater during daylight hours than at night. 101. Algae whose rate of photosynthesis varies on a 24-hour basis even when they are under constant light constitute evidence against the hypothesis that it is alterations in light that control biological cycles. Therefore choice E is the best answer. Choices A and B describe biological cycles, but provide no evidence about what controls them. Choice C says that cycles can become adapted to new patterns of light, weakly supporting the hypothesis that alterations in light control cycles. Finally, choice D provides evidence against a different hypothesis, namely, that it is the cell nucleus of single-cell plants that controls their biological cycles. 题目的结论关键一句话是alteration in the intensity of incident light is the stimulus that controls these daily biological rhythms. But there is much evidence to contradict this hypothesis. --就是在有光线下的不段变更，是控制这些每天的生物节奏刺激物。但是有很多证据都与这个猜想有矛盾。那不是只要有题目反驳这个不就行拉，我开始选B的，因为B说动物都可以在黑夜（无光线下）活动，那么就是他们都可以在黑夜里controls these daily biological rhythms，不需要光线都可以，不是选这个么？ 而E：Even when exposed to constant light intensity around the clock, some algae display rates of photosynthesis that are much greater during daylight hours than at night.即使暴露在光线中海藻在白天下的光合作用比在黑夜里的大。其实是支持结论啊，因为都是说有光线才可以CONTROL|！ 请哪位NN指教！ | 
