What conditions would result in a change in the frequency of a specific allele in a population?

Evolution is the change in allele frequency over time in a population of organisms. By mutation, genetic drift, gene flow and natural selection.

Evolution.

genetic drift, differential migration, gene flow, mutations and non-random mating

Tall people in a population preferentially marry other tall people and do not marry people who are short or average height.

If this happens then Natural Selection occurs because Natural Selection is the increase or decrease in allele frequencies due to the impact of the environment.The above answer is partially true. An...