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【单选题】
在所有的灵长类动物中，人类的智力无疑高居榜首，但在所有的灵长类动物中，也只有人类会为阿尔茨海默症所困。上海的研究小组日前发表论文指出，这两者可能密不可分。他们分析了90名祖先来自非洲、亚洲或欧洲的志愿者的基因组后发现，大约在距今20万到5万年间，与人类大脑发育相关的6个基因发生显著改变。这会增加神经元的连接性，令现代人演变得更聪明。然而，也正是这6个变异的基因，令阿尔茨海默症变得更复杂难解。这段文字主要介绍（）。
A.
人类与其他灵长类动物的差别
B.
人类大脑发育的关键阶段
C.
现代人变聪明的原因
D.
阿尔茨海默症与基因变异的关系
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参考解析：
刷刷题刷刷变学霸
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【单选题】Section BDirections: There are 2 passages in this section．Each passage is followed by some questions or unfinished statements．For each of them there are four choices marked A, B, C and D．You should de...
A.
to be collaborative and altruistic
B.
to act independently and individually
C.
to understand cooperation just as man does
D.
to know how to achieve success with coordinated action
【单选题】In a purely biological sense, fear begins with the body’’s system for reacting to things that can harm us—the so-called fight-or-flight response. "An animal that can’’t detect danger can’’t stay alive...
A.
reactions of humans and animals to dangerous situations are often unpredictable
B.
memories of significant events enable people to control fear and distress
C.
people’’s unpleasant memories are derived from their feelings of fear
D.
the amygdala plays a vital part in human and animal responses to potential danger
【单选题】下述有关运动神经元病的表述中不正确的是（）
A.
上、下运动神经元损害可同时并存
B.
家族性少见
C.
锥体束变性从高位脊髓向下或向上发展
D.
括约肌功能通常受影响
E.
可出现延髓麻痹