Some men are color-blind because they inherit a particular recessive gene from their mother. that recessive gene is carried on

X chromosome

Explanation:

In humans, sons always get one copy of the X chromosome from the mother and the Y chromosome from the father. Therefore, X-linked traits in males are inherited from mothers. Color-blindness is an X-linked recessive disease in which the responsible gene is present on the X chromosome. Sons get an X-linked gene for the colorblindness from a carrier or the affected mothers. For example, a female with X^cX would give the X^c chromosome to half of her sons.

b

explanation:

the answer to your question is:

c. complementary base-pairing