Scientific study of human population is called

Which one of the following population attributes contributes to an increase in population density?

$A$ biologist studied the population of rats in a barn. He found that the average natality was $250$, average mortality $240$, immigration $20$ and emigration $30$. The net increase in population is

The most important factor which determined the increase in human population in India during the $20^{\text{th}}$ century.

If a population has just been established in an ecosystem,which of the following factors will have the greatest impact?

The geometric representation of age structure is a characteristic of: