Eye color is also determined by genes. Brown eyes are dominant, and blue eyes are recessive. What must be true for two brown-eyed parents to produce a blue-eyed child?
A) One person passes on the blue-eye allele.
B) They each pass on the blue-eye allele.
C) One person's parents are blue-eyed.
D) One person's grandparents are blue-eyed.

answer:

C) One person's parents are blue-eyed.

Explanation:

You need a working HERC2 and a working OCA2 to have brown eyes. Because the two genes depend on each other, it is possible for someone to actually be a carrier of a dominant trait like brown eyes. And if two blue eyed parents are carriers, then they can have a brown eyed child.

I think that it's D because grandparents can pass down genes.

a change in inherited characteristics of biological populations over successive generations.