听力原文： There are over 6,000 million people in the world today, and the total is increasing at the rate of more than 89 million a year. The population is growing more quickly in some parts of the world than others. The continents with the fastest growth rates are Latin America and Africa. Asia comes third but because its present population is so large it is there that by far the greatest number of people will be added before the end of the century. The main reason for the population explosion is not so much a rise in birth rates as a fall in death rates as a result of improvements in public health services and medical care. The sudden increase in the population of the developing countries has come at a difficult time. Even if their population had not grown so fast they would have been facing a desperate struggle to bring the standard of living of their people to the point at which there was enough food, housing, education, medical care and employment for everyone to have a reasonable life. The most pressing problem created by the rapid increase in population is a shortage of food. Over the past two years the total amount of food has decreased, and of course the total amount of food per person has decreased even more sharply. As more and more babies born in developing countries have been surviving infancy, there is a shortage of schools and teachers, hospitals and doctors. Farming land is becoming scarce, and there are too few jobs and unemployment leads to further poverty. This talk covers each of the following topics EXCEPT ______