Final answer:
Population variance is influenced by genetic drift, natural selection, mutation rate, and allele frequencies.
Step-by-step explanation:
Population variance is influenced by genetic drift, natural selection, mutation rate, and allele frequencies. Genetic drift is the random change in allele frequencies that occurs in small populations. Natural selection is the process by which certain alleles are favored or selected for, leading to changes in allele frequencies over time. Mutation rate refers to the rate at which new genetic variations arise in a population. Allele frequencies reflect the proportions of different alleles in a population.