The correct option is Births - Deaths + In Migration - Out Migration.
Explanation
Population growth refers to the change in the number of inhabitants of a territory during a specific period. This change is measured using two distinct concepts: Natural Growth and Actual Growth.
- Natural Growth of Population: This is the population increase determined solely by the difference between births and deaths in a particular region between two points in time. It does not account for migration.
Formula: Births - Deaths - Actual Growth of Population: This metric reflects the true change in population size by incorporating both natural increase and the net effect of migration. It accounts for people moving into the region (In Migration) and people moving out of the region (Out Migration).
Formula: (Births - Deaths) + In Migration - Out Migration
Thus, the expression that correctly represents the 'Actual Growth of Population' is Births - Deaths + In Migration - Out Migration.
Key Takeaway: Natural Growth is driven purely by biological factors (fertility and mortality), whereas Actual Growth includes both biological factors and the mechanical factor of mobility (migration).