In chickens, two different genes, R/r and P/p, interact to affect comb shape.

The genotype rrpp gives single comb, R-P-, gives walnut or buttercup comb, rrP- gives a pea comb and R- pp gives a rose comb. The dash (-) can be filled in with either the dominant or recessive allele.

What phenotypic ratio would be produced from a cross between a heterozygous walnut combed chicken and one that has a single comb?




Select one:
a. 1 walnut: 1 rose: 1 pea: 1 single
b. 9 walnut: 3 rose: 3 pea: 1 single
c. 1 walnut: 1 single
d. 3 walnut: 1 single