The correct answer is: frequency of heterozygotes.
The Hardy-Weinberg equation is used to calculate the genetic variation of a population at equilibrium. If the alleles are A and a, p is the frequency of the allele A and q is the frequency of the allele a. Hardy-Weinberg equation for alleles A and a: p² + 2pq + q² = 1 p² is the frequency of the homozygous genotype AA, 2pq is the frequency of the heterozygous genotype Aa and q² is the frequency of the homozygous genotype aa. p²+2pq+q²=(p+q)²=1 p+q=1