If young people leave an area in large numbers, what effect can occur on future births?

Correct answer: Future births may decrease.

Answer: A. Young people often form an important part of the reproductive-age and working-age population. If many of them leave an area, the number of people who could have children there may become smaller. After a time, this can reduce the number of births in that area, although the exact result also depends on the age distribution, birth rate and whether other people move in. A is correct because it says births may decrease, not that they must decrease in every case. B is incorrect because youth out-migration cannot guarantee that births will double. C is incorrect because leaving of young people does not make the death rate zero. D is incorrect because out-migration does not always stop in-migration; both movements can occur. The key link is migration changing age structure, which can influence later births. Memory cue: fewer reproductive-age residents can mean fewer future births.