Which statement best defines net migration and its effect on population figures?

• A. Net migration is the total number of people living in a country.
• B. Net migration equals in-migrants minus out-migrants; it can increase or decrease population and shift age structure.
• C. Net migration only increases population, never decreases.
• D. Net migration only concerns movement within a country.

Answer: (B)

Net migration is the balance between people entering and leaving a country, calculated as in-migrants minus out-migrants. This balance can make the population grow if more people arrive than depart, or shrink if more depart than arrive. It can also change the age structure because migrants tend to cluster in certain age groups, often increasing the number of working-age people or altering the median age. The other statements miss key points: one describes total population rather than the movement balance; another wrongly says net migration only increases population; and another confuses it with movement within a country rather than across borders.