Question

The allele for a widow’s peak has complete dominance over the allele for a straight hairline (w). What is the probability of two parents heterozygous for a widow’s peak (Ww) having an offspring with a widow’s peak? A) 75 percent B) 50 percent C) 0 percent D) 25 percent

Answer 1

First you would make a cross for this. Which would result in WW, Ww, wW, and ww. Your answer would be 75 percent. You could do the same thing with using it similarly to the distributive property. 

Answer 2

Option A, 75 percent

Step-by-step explanation:

Given -

Allele for widow’s peak (W) is completely dominant over the allele for a straight hairline (w).

A cross is carried between two parents that are heterozygous for a widow’s peak

Thus, the offspring produced by the cross between two parents with genotype "Ww" is

Ww * Ww

WW, Ww, Ww, ww

Except "ww" genotype all the remaining offspring have widow's peak.

Thus, the probability of two parents heterozygous for a widow’s peak (Ww) having an offspring with a widow’s peak is

`(3)/(4) * 100\\0.75*100\\75`%

Hence, option A is correct.