Question

cross a heterozygous individual with a homozygous recessive one determine the genotype ratio and phenotype ratio of their offspring

Answer 1

Let's have our alleles be J = dominant, j = recessive. And for fun let's make the dominant phenotype black coat, the recessive brown coat.

Heterozygous x homozygous recessive

= Jj x jj

Punnett square:

J j

j Jj jj

j Jj jj

Genotypic ratio: 2 Jj : 2 jj, or a one-to-one ratio of Jj to jj.

Phenotypic ratio: 2 black : 2 brown, or a one-to-one ratio of black to brown.