複選題6. Red-green color blindness is a sex-linked recessive trait (i.e., the responsible gene is on the X chromosome). From a marriage between a woman heterozygous for color-blindness gene and a normal vision man, which of the following predictions for their children is correct? (A) all the boys are color blind (B) half of the boys are color blind (C) half of the girls have normal vision (D) ail the girls are heterozygous carrier