Final answer:
Gene flow is the process that can introduce new alleles into a population and also a reason why individuals in different populations of the same species resemble one another.
Step-by-step explanation:
Gene flow is the process that can introduce new alleles into a population and also a reason why individuals in different populations of the same species resemble one another.
Gene flow occurs when individuals or gametes migrate from one population to another, bringing their alleles with them. This can result in the transfer of new genetic variation to different populations, causing individuals in those populations to have similar traits.
For example, gene flow can occur when pollen from a plant is carried by wind or birds to pollinate plants in another population. Similarly, animals that migrate to different habitats can introduce their alleles to populations in those locations.