Which of the following problems do immigration and emigration pose for demographers?
a. demographers must provide for more city services.
b. demographers cannot identify the age structure of immigrants.
c. demographers find it difficult to make predictions about populations.
d. demographers study growth rates, age structures, and geographic distributions of populations.

c. Demographers find it difficult to make predictions about populations.

Explanation:

This is one of the complications that demographers have when it comes to immigration and emigration. Immigration and emigrations are two processes by which the population of a place can change. Due to this constant fluctuation, demographers can find it very difficult to make predictions about populations.

b. lithosphere, asthenosphere, mesosphere   is the answer most likely