When applying the Hardy-Weinberg law to a gene with dominant and recessive alleles,calculation of the allele frequencies always begins by writing the frequency of the _ phenotype,then taking the _ of this to obtain the frequency of the recessive allele.

Question

When applying the Hardy-Weinberg law to a gene with dominant and recessive alleles,calculation of the allele frequencies always begins by writing the frequency of the _____________________ phenotype,then taking the _____________________ of this to obtain the frequency of the recessive allele.