How is it possible to explain one parent with black hair, one parent with brown hair, and a kid with blonde hair

The parents had traces of blond genes that werent as dominant

Explanation:

I put the punnet square below

the lowercase b is blond

answer; i believe that the correct answer is ; males are hemizygous for the x chromosome;

as in mitosis, dna replication occurs during interphase.   in meiosis, it occurs specifically in s phase of interphase 1.