EVERYDAY SCIENCE

Detailed explanation-1: -Populations gain individuals through births and immigration. They lose individuals through deaths and emigration. These factors together determine how fast a population grows.

Detailed explanation-2: -Immigration is the movement of individuals into an area and emigration is movement of individuals out of an area. Therefore, natality and immigration will increase population.

Detailed explanation-3: -Immigration describes individuals moving into the population while emigration describes individuals exiting the population. If immigration rates are higher than emigration rates, the population increases, whereas if emigration rates are higher than immigration rates, the population size decreases.

Detailed explanation-4: -Immigration and emigration contribute to population change not only by altering the number of individuals in the country at a given time (direct contribution) but also by affecting natural change (indirect contribution).

Detailed explanation-5: -Overall, population grows or shrinks through two very basic components – natural change (births minus deaths) and migration (domestic plus international).