Population change refers to change in the number of people living during a specific period of time. Main factors influencing population change are:

a. The difference between the birth rate and death rate (natural growth rate) is the main cause of population change.

b. Migration also brings about population change. Migration refers to the movement of people in and out of an area. People may move within a country or between countries in search of better employment opportunities or to escape unsafe conditions within their original territory of residence.