Meiosis is key to genetic differences within a gene pool that helps to drive natural selection. Consider the processes involved in meiosis and sexual reproduction. all BUT ONE of the choices contributes to genetic differences in a sexually reproducing population.

A. crossing over
B. fertilization
C. DNA replication
D. random assortment

(the picture is the venom diagram that was put with the question)

C, DNA replication

Explanation:

Crossing over, random assortment, and fertilization all contribute to genetic diversity. However DNA replication is the synthesis of identical DNA strands.

the father in the first generation probably had the recessive colorblind trait in his x chromosome. if he and his wife both had the colorblind trait, even if she had 1 recessive and 1 dominant, then that trait would be passed on to their kids.

(since you didn't attach the family tree this is just an assumption)

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).