Genes for the M and L pigments are on the X chromosome, and males have only one X chromosome, while women have two. This explains why
A) men are more likely than women to have visual impairments.
B) women are more likely than men to have visual impairments.
C) women and men are about equally likely to have visual impairments.
D) the incidence of visual impairments is most affected by age.

Question

Quizplus · Accepted Answer

Men are more likely to have color vision deficiencies related to the M and L pigments because they have only one X chromosome. If the X chromosome a man inherits has a defect in the gene for these pigments, there is no second X chromosome to provide a potentially healthy copy, unlike in women who have two X chromosomes.

Genes for the M and L Pigments Are on the X