Final answer:
Stabilizing selection can result in a stable genetic polymorphism if heterozygotes have the highest fitness.
Step-by-step explanation:
Selection can result in a stable genetic polymorphism if the heterozygotes genotype has the highest fitness. When heterozygotes have a higher fitness, this maintains genetic variation in a population as both homozygous genotypes are not favored. With stabilizing selection, the average phenotype is favored, selecting against extreme variation. This leads to a decrease in the population's genetic variance over time.