Being a man has always been dangerous. There are about 105 malesborn for every 100 females, but this ratio drops to near balance at the age ofmaturity, and among 70-year-olds there are twice as many women as men. But thegreat universal of male mortality is being changed. Now, boy babies survivealmost as well as girls do. This means that, for the first time, there will bean excess of boys in those crucial years when they are searching for a mate.More important, another chance for natural selection has been removed. Fiftyyears ago, the chance of a baby surviving depended onits weight. A kilogram too light or too heavy meant almost certain death. Todayit makes almost no difference. Since much of the variation is due to genes, onemore agent of evolution has gone. 　　There is another way to commit evolutionary suicide: stay alive, buthave fewer children. Few people are as fertile as in the past. Except in somereligious communities, very few women have 15 children. Nowadays the number ofbirths, 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 shows whatis happening. The country offers wealth for a few in the great cities andpoverty for the remaining tribal peoples. The grand mediocrity of today―everyonebeing the same in survival and number of offspring means that natural selectionhas 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 hasarrived. Strangely, it has involved little physical change. No other speciesfills so many places in nature. But in the past 100,000 yearseven thepast 100 yearsour lives have been transformed but our bodies have not. We did notevolve, because machines and society did it for us. Darwin had a phrase todescribe those ignorant of evolution: they look at anorganic being as average looks at a ship, as at something wholly beyond hiscomprehension. No doubt we will remember a 20th century way of life beyondcomprehension for its ugliness. But however amazed our descendants may be athow far from Utopia we were, they will look just like us. 　　15. What used to be the danger in being a man according to the firstparagraph? 　　[A]A lack of mates. 　　[B]A fierce competition. 　　[C]A lower survival rate. 　　[D]A defective gene. 　　16. What does the example of India illustrate? 　　[A]Wealthy people tend to have fewer children than poor people. 　　[B]Natural selection hardly works among the rich and the poor. 　　[C]The middle class population is 80% smaller than that of thetribes. 　　[D]India is one of the countries with a very high birth rate. 　　17. The author argues that our bodies have stopped evolvingbecause____. 　　[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 　　18. Which of the following would be the best title for the passage? 　　[A]Sex Ration Changes in Human Evolution 　　[B]Ways of Continuing Man s Evolution 　　[C]The Evolutionary Future of Nature 　　[D]Human Evolution Going Nowhere

　　Being a man has always been dangerous. There are about 105 malesborn for every 100 females, but this ratio drops to near balance at the age ofmaturity, and among 70-year-olds there are twice as many women as men. But thegreat universal of male mortality is being changed. Now, boy babies survivealmost as well as girls do. This means that, for the first time, there will bean excess of boys in those crucial years when they are searching for a mate.More important, another chance for natural selection has been removed. Fiftyyears ago, the chance of a baby surviving depended onits weight. A kilogram too light or too heavy meant almost certain death. Todayit makes almost no difference. Since much of the variation is due to genes, onemore agent of evolution has gone. 　　There is another way to commit evolutionary suicide: stay alive, buthave fewer children. Few people are as fertile as in the past. Except in somereligious communities, very few women have 15 children. Nowadays the number ofbirths, 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 shows whatis happening. The country offers wealth for a few in the great cities andpoverty for the remaining tribal peoples. The grand mediocrity of today―everyonebeing the same in survival and number of offspring means that natural selectionhas 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 hasarrived. Strangely, it has involved little physical change. No other speciesfills so many places in nature. But in the past 100,000 yearseven thepast 100 yearsour lives have been transformed but our bodies have not. We did notevolve, because machines and society did it for us. Darwin had a phrase todescribe those ignorant of evolution: they look at anorganic being as average looks at a ship, as at something wholly beyond hiscomprehension. No doubt we will remember a 20th century way of life beyondcomprehension for its ugliness. But however amazed our descendants may be athow far from Utopia we were, they will look just like us. 　　15. What used to be the danger in being a man according to the firstparagraph? 　　[A]A lack of mates. 　　[B]A fierce competition. 　　[C]A lower survival rate. 　　[D]A defective gene. 　　16. What does the example of India illustrate? 　　[A]Wealthy people tend to have fewer children than poor people. 　　[B]Natural selection hardly works among the rich and the poor. 　　[C]The middle class population is 80% smaller than that of thetribes. 　　[D]India is one of the countries with a very high birth rate. 　　17. The author argues that our bodies have stopped evolvingbecause____. 　　[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 　　18. Which of the following would be the best title for the passage? 　　[A]Sex Ration Changes in Human Evolution 　　[B]Ways of Continuing Man s Evolution 　　[C]The Evolutionary Future of Nature 　　[D]Human Evolution Going Nowhere