单选题
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, boy 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 have 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 past 100,000 years—even the past 100 years—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 a savage 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.
单选题
What used 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..
D.A defective gene.
【正确答案】
C
【答案解析】[解析] 文章第一段开头是答题的关键：Being a man has always been dangerous...But the great universal of male mortality is being changed.可见，男性的出生率高于女性，但是随着年龄增加，男女比例呈明显下降趋势。作者试图用这些数据表明，生为男人的危险并不是在于寻找配偶的困难，而是男性的死亡率远远高于女性。
单选题
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 the tribes.
D.India is one of the countries with a very high birth rate.