Answer: An animal moves to a new population and mates.
A gene flow refers to the transfer of genetic material from one population to the other population. The introduction of genetic material is because of interbreeding that occur in one population of a species with other population. Gene flow results due to immigration of population of species to a new location. These individuals will mate with the native species of the location and transfer their own genes.
Hence, an animal moves to a new population and mates is an example of gene flow.