Explain the four factors that produce changes in population size.

Answer 1

immigration
war
emigration
birth rate
quality of health care

Answer 2

so many possible factors... I'm not sure you meant "Explain" or "List", if you want explanation, you should of gave us the list of 4 factors.

*Innervation of new & efficiency agriculture technology (more food - worldwide)
*Government intervention (such as the One Child Policy in China)