Which factors drive sustained population growth in a region?

• A. Natural increase and possibly net migration.
• B. Natural increase only.
• C. Net migration only.
• D. Random fluctuations.

Answer: (C)

Sustained population growth comes from two processes: natural increase (births minus deaths) and net migration (immigration minus emigration). In many regions, birth rates are not high enough to drive ongoing growth on their own, so a positive net migration becomes the key factor that keeps increasing the population over time. Immigration adds people regardless of local birth trends, making growth more likely to continue. Natural increase can contribute when birth rates are high, but it isn’t as reliable for long-term growth across different contexts. Random fluctuations don’t provide a consistent driver of growth, whereas net migration can sustain it year after year.