The shaded individuals in the pedigree diagram below are color-blind. The
only unknown is whether the mother in the first generation has normal color
vision.
1.
II.
What is true about the mother?
4
OA. She must be color-blind.
B. She could be homozygous for normal color vision.
OC. She could be heterozygous for color blindness.
O D. She must have normal color vision.