Movement of genes between populations.

• A. Inbreeding
• B. Founder effect
• C. Genetic drift
• D. Gene flow

Answer: (D)

Gene flow is the movement of genes between populations. It happens when individuals migrate or when their gametes (like pollen or seeds) mix with another population, introducing new alleles into the recipient gene pool. This exchange tends to make allele frequencies more similar across populations, reducing differences between them. In contrast, inbreeding is mating among relatives within a population and does not involve gene flow between populations. The founder effect describes a new population starting from a small number of individuals, leading to reduced genetic variation. Genetic drift is random change in allele frequencies from one generation to the next, especially in small populations, and it isn’t about movement between populations.