Which process can increase an area's population because people come from outside?

Correct answer: In-migration

Direct answer: Option A, in-migration. In-migration occurs when people enter a particular area from another place to live there. These newcomers are added to the population of the area they enter, so in-migration can increase its population. Option A is correct because it directly describes people coming into the area. Option B is wrong because out-migration means people leave an area, which can reduce its local population. Option C is wrong because deaths remove people from the population rather than bring new residents. Option D is wrong because drought is an environmental condition; it may influence movement, but it is not the population process named in the question. Notice that the question asks about people coming from outside, so focus on the direction of movement. Memory cue: “in” means entering; in-migration brings people in. The final population also depends on births, deaths, and people leaving, but the process asked here is specifically in-migration.