In Mendel's work with peas, an F1 hybrid (smooth yellow) was crossed to the recessive (wrinkled green) parent type. In terms of color, what were the frequencies of the phenotypes in the offspring of this cross?

Explanation:

Given;

Here the parents are; an F1 hybrid smooth yellow and recessive wrinkled green;

Smooth yellow is an F1 hybrid,

lets assume smooth yellow as; SsYy

S= smooth; S is dominant over s,

Y= yellow; Y is dominant over y.

so wrinkled green is  ssyy;

so offspring will be

gametes of SsYy  are; SY, Sy, sY and sy

gamets of ssyy = sy type only

so offspring will be;

genotype ; SsYy, Ssyy, ssYy, ssyy,

phenotype;  smooth yellow (SsYy), Smooth green (Ssyy), wrinkled yellow (ssYy) and wrinkled green (ssyy).

So frequencies of the phenotypes in the offspring of this cross are 25% each.

since there are no options posted i'll give you a few examples.

a dolphin's flipper, bird's wing, cat's leg.