Greg has several siblings that all look very different from one another. However, he can see different traits from his mother and father in each of them.
What contributed to these differences between his siblings?

A. Both prophase 1 and prophase 2 occurred during the formation of his parents' sex cells.
B. Independent assortment occurred during the formation of his parents' sex cells.
C. Independent assortment occurred during fertilization of each egg cell.
D. In mitosis during growth, crossing over caused each child to develop differently.

Independent assortment and segregation of chromosomes during meiosis resulted in recombinant chromatids forming that resulted in gametes formed being vastly different from the original sequence of the chromosomes (gene locus remains constant but gene sequence changed) resulting in resultant zygote to have different alleles which resulted in both siblings being different.

However, both siblings looks like their parents as zygote formed are a combination of 1 unit of chromosomes from each parent. Hence, offsprings will have traits from each parent.