Frequency of an allele in an isolated population may change due to:
A) Genetic drift
B) Gene flow
C) Mutation
D) Natural selection

Genetic drift:
Genetic drift refers to the random fluctuations in allele frequencies within a population. It occurs due to chance events, especially in small populations. Genetic drift can lead to the loss or fixation of alleles, resulting in a change in allele frequency over time. The impact of genetic drift is more pronounced in isolated populations with limited gene flow.

Gene flow:
Gene flow is the transfer of alleles from one population to another through the migration of individuals. It can introduce new alleles into a population or alter the frequency of existing alleles. In an isolated population, gene flow may be limited, reducing the exchange of genetic material. This can result in changes in allele frequencies if individuals with different alleles migrate in or out of the population.

Mutation:
Mutation is the ultimate source of genetic variation. It refers to changes in the DNA sequence of an organism's genome. Mutations can create new alleles or modify existing ones. In an isolated population, the accumulation of mutations over successive generations can lead to changes in allele frequencies. However, the impact of mutation alone on allele frequency change is relatively slow compared to other factors.

Natural selection:
Natural selection is the process by which certain heritable traits become more or less common in a population over generations. It occurs when individuals with certain advantageous traits have higher reproductive success, leading to the increase in frequency of those traits in subsequent generations. Natural selection can act on different alleles, favoring those that confer a survival or reproductive advantage. This can result in changes in allele frequencies within an isolated population.

Conclusion:
In an isolated population, the frequency of an allele can change due to genetic drift, gene flow, mutation, and natural selection. Genetic drift and limited gene flow can cause random fluctuations in allele frequencies, while mutation introduces new alleles or modifies existing ones. Natural selection acts on advantageous traits, favoring certain alleles over others. The interplay of these factors determines the dynamics of allele frequency changes in isolated populations.

A) genetic drift