题目

15．某同学总结了四点有关减数分裂、染色体、DNA的知识点，其中不正确的是   A．次级精母细胞中的DNA分子正好和正常体细胞的DNA分子数目相同   B．减数第二次分裂后期，细胞中染色体的数目等于正常体细胞中的染色体数目   C．初级精母细胞中染色体的数目正好和DNA分子数目相同   D．任何一种哺乳动物的细胞中染色体的数目和着丝粒的数目相同Decision-making under StressA new review based on a research shows that acute stress affects the way the brain considers the advantages and disadvantages, causing it to focus on pleasure and ignore the possible negative (负面的) consequences of a decision.The research suggests that stress may change the way people make choices in predictable ways.“Stress affects how people learn,” says Professor Mara Mather. “People learn better about positive than negative outcomes under stress.”For example, two recent studies looked at how people learned to connect images(影像) with either rewards or punishments. In one experiment, some of the participants were first stressed by having to give a speech and do difficult math problems in front of an audience; in the other, some were stressed by having to keep their hands in ice water. In both cases, the stressed participants remembered the rewarded material more accurately and the punished material less accurately than those who hadn’t gone through the stress.This phenomenon is likely not surprising to anyone who has tried to resist eating cookies or smoking a cigarette while under stress –at those moments, only the pleasure associated with such activities comes to mind. But the findings further suggest that stress may bring about a double effect. Not only are rewarding experiences remembered better, but negative consequences are also easily recalled.The research also found that stress appears to affect decision-making differently in men and women. While both men and women tend to focus on rewards and less on consequences under stress, their responses to risk turn out to be different.Men who had been stressed by the cold-water task tended to take more risks in the experiment while women responded in the opposite way. In stressful situations in which risk-taking can pay off big, men may tend to do better, when caution weighs more, however, women will win.This tendency to slow down and become more cautious when decisions are risky might also help explain why women are less likely to become addicted than men: they may more often avoid making the risky choices that eventually harden into addiction.1.We can learn from the passage that people under pressure tend to ______.A. keep rewards better in their memoryB. recall consequences more effortlesslyC. make risky decisions more frequentlyD. learn a subject more effectively2.According to the research, stress affects people most probably in their ______.A. ways of making choices B. preference for pleasureC. tolerance of punishments D. responses to suggestions3.The research has proved that in a stressful situation, ______.A. women find it easier to fall into certain habitsB. men have a greater tendency to slow downC. women focus more on outcomesD. men are more likely to take risks