Prolonging Human Life
Prolonging human life has increased the size of the human population. Many
people alive today would have died of childhood diseases if they had been born
100 years ago. Because more people live longer, there are more people around at
any given time. In fact, it is a decrease in death rates, not an increase in
birthrates that has led to the population explosion. Prolonging
human life has also increased the dependency load. In all societies, people who
are disabled or too young or too old to work are dependent on the rest of
society to provide for them. In hunting and gathering cultures, old people who
failed to follow the others were left behind to die. In times of famine, infants
might be allowed to die because t A. an increase in birthrates B. the industrial development C. a decrease in death rates D. cultural advances
[单项选择]Mary felt {{U}}lonely{{/U}} after her husband died in a car accident. A. alone B. gloomy C. desolate D. separate
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