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离体神经纤维某一部位受到适当刺激时，受刺激部位细胞两侧会出现暂时性的电位变化产生神经冲动。图示该部位受刺激前后，膜两侧电位差的变化。请回答： 神经冲动在突触的传递受很多药物的影响。某药物能阻断突触传递，如果它对神经递质的合成、释放和降解(或再摄取)等都没有影响，那么导致神经冲动不能传递的原因可能是该药物影响了神经递质与______结合。
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Passage One At some time in your life, you may have a strong desire to do something strange or terrible. However, chances are that you don’t act on your impulse, but let it pass instead. You know that to commit the action is wrong in some way and that other people will not accept your behavior. Perhaps the most interesting thing about the phenomenon of tabo0 behavior is how it can change over the years within the same society, how certain behavior and attitude once considered taboo can become perfectly acceptable and natural at another point in time. Topics such as death, for example, were once considered so upsetting and unpleasant that it was a taboo to even talk about them. Now with the publication of important books such as On Death and Dying and Learning to Say Goodbye, people have become more aware of the importance of expressing feelings about death and, as a result, are more willing to talk about this taboo subject. One of the newest taboos in American society is the topic of fat. Unlike many other taboos, fat is a topic that Americans talk about constantly. It’s not taboo to talk about fat; it’s taboo to be fat. The "in" look is thin, not fat. In the work world, most companies prefer youthful-looking, trim executives to sell their images as well as their products to the public. The thin look is associated with youth, vigor, and success. The fat person, on the other hand, is thought of as lazy and lacking in energy, self- discipline, and self-respect. In an image-conscious society like the U.S., thin is "in", fat is "out". It’s not surprising, then, that millions of Americans have been obsessed with staying slim and "in shape". The pursuit of a youthful physical appearance is not, however, the sole reason for Americans’ fascination with diet and exercise. Recent research has shown the critical importance of diet and exercise for personal health. As in most technologically developed nations, the life style of North Americans has changed dramatically during the course of the last century. Modem machines do all the physical labor that people were once forced to do by hand. Cars and buses transport us quickly from point to point. As a result of inactivity and disuse, people’s bodies can easily become weak and vulnerable to disease. In an effort to avoid such a fate, millions of Americans are spending more of their time exercising. Based on the ideas presented in the passage we can conclude "being fat" ______ in American society.
简述法律规则的逻辑结构。
气候变化与生态系统的碳循环密切相关。下表为A、B两个不同时期陆地生态系统与大气环境的碳交换情况。 时期 碳吸收量(kgC·a-1) 碳释放量(kgC·a-1) A B 1.20×1014 1.20×1014 1.20×1014 1.26×1014 人们正在积极开发新能源以减少碳排放。如“叶绿素太阳能电池”是模仿类囊体吸收光能的特性而制造的，类囊体吸收光能的过程发生在光合作用的______阶段；又如经改造的蓝藻能在细胞内将光合作用产生的______直接发酵转化为燃料乙醇。
从一种生物的细胞中提取得到甲、乙两种有机物，甲的含量大于乙，在适当的条件下用人的胃液处理，甲分解而乙不分解；分析甲、乙的化学成分，甲含有氮和硫，乙含有氮和磷；甲、乙两种物质遇碘都不变蓝；从来源看，在细胞膜上有甲而没有乙。据此回答下列问题： 请举例说明在洋葱根尖分生区细胞中主要由甲、乙两种物质组成的结构______(举一例)。
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