题干

在a、b、c、d条件下,测得某植物种子萌发时CO2和O2体积变化的相对值如下表.若底物是葡萄糖,则下列叙述中正确的是(  )

a

b

c

d

CO2释放量

10

8

6

7

O2吸收量

0

3

4

7

A:a条件下,呼吸产物除CO2外还有酒精和乳酸

B:b条件下,有氧呼吸消耗的葡萄糖比无氧呼吸多

C:c条件下,无氧呼吸最弱

D:d条件下,产生的CO2全部来自线粒体

上一题 下一题 0.0难度 选择题 更新时间:2018-11-29 11:25:49

答案(点此获取答案解析)

D

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    Fear may be felt in the heart as well as in the head, according to a study that has found a link between the cycles of a beating heart and the chance of someone feeling fear.

    Tests on healthy volunteers found that they were more likely to feel a sense of fear at the moment when their hearts are contracting(收缩)and pumping blood around their bodies, compared with the point when the heartbeat is relaxed. Scientists say the results suggest that the heart is able to influence how the brain responds to a fearful event, depending on which point it is at in its regular cycle of contraction and relaxation.

    Sarah Garfinkel at the Brighton and Sussex Medical School said: “Our study shows for the first time that the way in which we deal with fear is different depending on when we see fearful pictures in relation to our heart.”

    The study tested 20 healthy volunteers on their reactions to fear as they were shown pictures of fearful faces. Dr Garfinkel said, “The study showed that fearful faces are better noticed when the heart is pumping than when it is relaxed. Thus our hearts can also affect what we see and what we don't see and guide whether we see fear.”

    To further understand this relationship, the scientists also used a brain scanner(扫描仪)to show how the brain influences the way the heart changes a person's feeling of fear.

    “We have found an important mechanism by which the heart and brain ‘speak' to each other to change our feelings and reduce fear,” Dr Garfinkel said.

    “We hope that by increasing our understanding about how fear is dealt with and ways that it could be reduced, we may be able to develop more successful treatments for anxiety disorders, and also for those who may be suffering from serious stress disorder.”