Answer: A) immigration, emigration
Step-by-step explanation:
The gene flow can also be defined as the gene migration from one generation to another. The composition of the gene pool changes. Due to the genetic variability at the individual level the variation in the gene pool also increases. The gene flow occurs mainly because of migration of organisms from one region to another.
Immigration can be defined as the introduction of organisms in a new habitat. Emigration can be defined as the migration or departure of the organisms to a new habitat from their native habitat. Immigration will add new genes to the new habitat population gene pool. Emigration will limit the genetic variation in the gene pool.
On the basis of the above information, immigration is the flow of genes into an area whereas emigration is the flow of genes out of an area.