Red-green color-blindness is an X-linked recessive condition. Juliet has a bit of difficulty passing the red-green color distinction test when she tries to get her driver's license. She has two children with a man who is not color blind. Neither Juliet's son (Henry) nor daughter (Roxanne) is color blind. Henry and Roxanne have normal karyotypes. Roxanne has a son who is color blind.

Required:
a. What is Juliet's genotype for the color-blindness allele? How would you explain her partial color blindness?
b. Why aren't Henry and Roxanne color blind?