Which can be a direct cause of population decrease in an area?

Correct answer: Increase in deaths

The direct answer is B: an increase in deaths can directly cause population decrease. Deaths remove people from the population of an area. If the number of deaths becomes greater than the number of births, natural change is negative and the population may decline. A is wrong because immigration, or in-migration, brings people into the area and normally increases its population. C is wrong because more births add people. D is also wrong because the arrival of people is an inflow and therefore adds to the local population. Migration and births can affect the final total, so “can” is the appropriate wording rather than “must.” The basic memory rule is: births and arrivals add; deaths and departures subtract. This rule helps distinguish immigration from out-migration and prevents confusion between movement into and movement out of an area.