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  3. Being a man has always been dangerous.There are about 105 males born for every 100 females, but this ratio drops to near balance

Being a man has always been dangerous.There are about 105 males born for every 100 females, but this ratio drops to near balance

admin2015-05-29  68
问题     Being a man has always been dangerous.There are about 105 males born for every 100 females, but this ratio drops to near balance at the age of maturity, and among 70-year-olds there are twice as many women as men.But the great universal of male mortality is being changed now, by babies survive almost as well as girls do.This means that, for the first time, there will be 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 years ago, 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 almost no difference.Since much of the variation is due to genes one more agent of evolution has gone.
    There is another way to commit evolutionary suicide: stay alive, but have fewer children.Few people are as fertile as in the past.Except in some religious communities, very few women has 15 children.Nowadays, the number of births, like the age of death, has become average.Most of us have roughly the same number of offspring.Again, differences between people and the opportunity for natural selection to take advantage of it have diminished India shows what is happening.The country offers wealth for a few in the great cities and poverty for the remaining tribal peoples.The grand mediocrity of today everyone being the same in survival and number of offspring means that natural selection has lost 80% of its power in upper-middle-class India compared to the tribes.
    For us, this means that evolution is over; the biological 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 year our lives have been transformed but our bodies have not.We did not evolve, because machines and society did it for us.Darwin had a phrase to describe those ignorant of evolution: they "look at an organic being as average looks at a ship, as at something wholly beyond his comprehension." No doubt we will remember a 20th century way of life beyond comprehension for its ugliness.But however amazed our descendants may be at how far from Utopia we were, they will look just like us.
The author argues that our bodies have stopped evolving because______.
选项 A、life has been improved by technological advance
B、the number of female babies has been declining
C、our species has reached the highest stage of evolution
D、the difference between wealth and poverty is disappearing
答案A
解析 本题可参照文章的第3段。从中可知，对于我们来说，这意味着进化已结束；生物学上的理想境界已经来临；令人奇怪的是，这种进化几乎不涉及身体的变化；过去10万年——甚至过去100年中，我们的生活发生了改变，但我们的身体却没有；我们没有进化，因为机器和社会代替我们进化了。据此可知，我们的身体已经停止进化的原因是机器和社会代替我们进化了，也就是先进的技术代替我们进化了。A项与文章的意思相符，因此A项为正确答案。
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