In red-green colorblindness, individuals cannot perceive the colors red and green in the same way as individuals with full color vision. Full color vision is coded by a dominant allele (B) on the X chromosome. Red-green colorblindness is caused by a recessive allele (b) on the X chromosome.

a. Identify the phenotype of a female with the genotype XBXb.
b. Identify the phenotype of a male with the genotype XBY.
c. Draw a Punnett square for the cross X uppercase B, X lowercase b crossed with X uppercase B, Y, and identify the following:
the percentage of offspring expected to be male and colorblind
the percentage of offspring expected to be female and colorblind
d. Explain why red-green colorblindness occurs more frequently in males than in females.