关于进化论在人们中的作用的那篇文章
Text 2Being a man has always been dangerous. There areabout 105 males born for every 100 females, but this ratio drops to near balanceat the age of maturity, and among 70-year-olds there are twice as many women asmen. But the great universal of male mortality is being changed. Now, boy babiessurvive almost as well as girls do. This means that, for the first time, there willbe an excess of boys in those crucial years when they are searching for a mate.More important, another chance for natural selection has been removed. Fifty yearsago, the chance of a baby (particularly a boy baby) surviving depended on its weight.A kilogram too light or too heavy meant almost certain death. Today it makes almostno difference. Since much of the variation is due to genes, one more agent of evolutionhas gone. There is another way to commit evolutionary suicide:stay alive, but have fewer children. Few people are as fertile as in the past. Exceptin some religious communities, very few women have 15 children. Nowadays the numberof births, like the age of death, has become average. Most of us have roughly thesame number of offspring. Again, differences between people and the opportunityfor natural selection to take advantage of it have diminished. India showswhat is happening. The country offers wealth for a few in the great cities and povertyfor the remaining tribal peoples. The grand mediocrity of today -- everyone beingthe same in survival and number of offspring -- means that natural selection haslost 80% of its power in upper-middle-class India compared to the tribes. For us, this means that evolution is over; thebiological Utopia has arrived. Strangely, it has involved little physical change.No other species fills so many places in nature. But in the pass 100,000 years-- even the pass 100 years -- our lives have been transformed but our bodies havenot. We did not evolve, because machines and society did it for us. Darwin had a phrase to describethose ignorant of evolution: they “look at an organic being as a savage looks ata ship, as at something wholly beyond his comprehension.” No doubt we will remembera 20th century way of life beyond comprehension for its ugliness. But however amazedour descendants may be at how far from Utopia we were, they will look just likeus. 55. Whatused to be the danger in being a man according to the first paragraph? [A] A lack of mates. [B] A fierce competition. [C] A lower survival rate.（C） [D] A defective gene. 56. Whatdoes the example of Indiaillustrate? [A] Wealthy people tend to have fewer childrenthan poor people. [B] Natural selection hardly works among therich and the poor. [C] The middle class population is 80% smallerthan that of the tribes.（B） [D] India is one of the countries with avery high birth rate. 57. Theauthor argues that our bodies have stopped evolving because ________. [A] life has been improved by technologicaladvance [B] the number of female babies has been declining [C] our species has reached the highest stageof evolution（A） [D] the difference between wealth and povertyis disappearing 58. Whichof the following would be the best title for the passage? [A] Sex Ratio Changes in Human Evolution [B] Ways of Continuing Man’s Evolution [C] The Evolutionary Future of Nature（D） [D] Human Evolution Going Nowhere
第二道题目为什么是B。
文中已经提出了
means that natural selection has lost 80% of its power in upper-middle-class India compared to the tribes. （ 意味着自然选择对上层社会的作用比部落的人的作用减少了百分之八十）
而B项说的是自然选择对富人和穷人都不起作用。
为什么~为什么~为什么，请告诉我，告诉我~~
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