If people leave an area and move out what effect may occur on that area's population?

Correct answer: Population may decrease

Direct answer: A, the population may decrease. When residents leave an area to live elsewhere, the movement is called outward migration or out-migration. Those people are removed from the population count of the area they leave. If departures are greater than arrivals, and births and deaths do not offset the difference, the area’s population can fall. Option A is correct because it states this possible effect carefully. Option B is wrong because people leaving cannot make the population always double; the result depends on the numbers entering and leaving. Option C is wrong because migration changes population size, not the physical area of land. Option D is wrong because people leaving do not automatically stop births; birth rate depends on births in relation to population and other conditions. A useful warning is that out-migration may reduce a place’s population even if the wider region or destination gains people.