A recessive gene located on the X chromosome is the cause of color blindness in affected individuals. Males are more likely to be colorblind than females because

A.
males have only one copy of the X chromosome.
B.
males have two copies of the X chromosome.
C.
females have no copies of the X chromosome.
D.
color blindness is associated with high testosterone levels.

A. males have only one copy of the X chromosome.