Answer the following passage:statistics show that the rapid growth in population creates problems for developing countries. it has been found that only when people's education and living standards begin to rise do birth rates begin to fall. now poor countries cannot afford social services and old age pensions, and people's incomes are so low that they have nothing to save for the furure. so people need their children to provide them with security in their old age. Having a large family can be a form of insurance Even when are still young. children can help on a small farm or a workshop apprentices improvement in public health services and medical care has assured that many more babies survive infancy and grow up. it has also helped the parents to live longer. No wonder people are being added to at both ends. These people have to be convinced that with smaller families, there will be more food, better schools, more employment and thus a better standard of living newspapers,television and radio programs should help in changing people's attitudes towards large families. Answer this question : what does the writer mean by "people are being added to at both ends"?