Answer:
The correct answer would be gene flow.
Gene flow in population genetics refers to the flow or movement of genetic material from one population to another.
It is also termed as gene migration.
It is caused by the migration of organisms from one place or population to another. For example, the migration of humans from one city or country to another.
In plants, it occurs when pollen is blown to new destinations.
It helps in increasing the overall genetic variation among the entire population.