Beanie Eyelash is a celebrity who does not have a widows peak, while Chris Hemsworth is a celebrity who does. What is a widows peak an example of? A single gene traits
B polygenic traits
C single allele genotypes
D polygenic genotypes

the father in the first generation probably had the recessive colorblind trait in his x chromosome. if he and his wife both had the colorblind trait, even if she had 1 recessive and 1 dominant, then that trait would be passed on to their kids.

(since you didn't attach the family tree this is just an assumption)