Answer: 50%
Color-blind is a x-linked recessive trait, that means you need to have all the X chromosome have the defective genes.
Male genes is XY. Since the only male have Y gene so we can say for certain that the X gene is from the mother. The mother is heterozygous which means only have 1 of 2 defective genes. Then the chance for the mother to give defective gene is 50%.
