Read the passage carefully, then choose the correct answers. No one knows the limits of population that the earth can support. Thomas Malthus, an English economist, developed a theory that became widely accepted in the nineteenth century. He suggested that because world population tended to increase more rapidly than the food supply, a continual strain was exerted upon available resources. Malthus cited wars, famines, epidemics, and other diseases as the usual limitations of population growth. ...

Read the passage carefully, then choose the correct answers.

No one knows the limits of population that the earth can support. Thomas Malthus, an English economist, developed a theory that became widely accepted in the nineteenth century. He suggested that because world population tended to increase more rapidly than the food supply, a continual strain was exerted upon available resources. Malthus cited wars, famines, epidemics, and other diseases as the usual limitations of population growth.

With recent advances in science and technology, including improved agricultural methods and great strides in medicine, some of the limiting factors in population growth have been lessened, with obvious results.

International organizations have put forward several recommendations to alleviate the problem of overpopulation, including an increase in food production, general economic development in target areas, and a decrease in birth rate. Most experts agree that it will be necessary to combine all three recommendations in an effort to affect a lasting solution.

According to the passage, why has overpopulation been caused?