题目信息
The chemical adenosine is released by brain cells when those cells are active. Adenosine then binds to more and more sites on cells in certain areas of the brain, as the total amount released gradually increases during wakefulness. During sleep, the number of sites to which adenosine is bound decreases. Some researchers have hypothesized that it is the cumulative binding of adenosine to a large number of sites that causes the onset of sleep.
Which of the following, if true, provides the most support for the researchers' hypothesis?
A:Even after long periods of sleep when adenosine is at its lowest concentration in the brain, the number of brain cells bound with adenosine remains very large.
B:Caffeine, which has the effect of making people remain wakeful, is known to interfere with the binding of adenosine to sites on brain cells.
C:Besides binding to sites in the brain, adenosine is known to be involved in biochemical reactions throughout the body.
D:Some areas of the brain that are relatively inactive nonetheless release some adenosine.
E:Stress resulting from a dangerous situation can preserve wakefulness even when brain levels of bound adenosine are high.
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正确答案：
B:Caffeine, which has the effect of making people remain wakeful, is known to interfere with the binding of adenosine to sites on brain cells.
科学家预言，连续的A物质绑定大量接收器导致了睡眠的开始
A 即使睡了很久，当A的浓度最低时，仍然有很多与A结合了的脑细胞保持很大。没有加强。
B 咖啡因影响A物质与大脑的接收器的绑定，导致人清醒。正确。
C 除了与sites结合，A还会参与人体的biochemical 反应，无关。
D 大脑的一些其他区域不怎么活跃。无关
E 压力可以让人保持清醒哪怕结合了的A浓度还是很高。削弱，排除。A浓度高应该会想睡才对
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