Billy and Johnny are brothers, but they do not look alike. Which one of the following pairs of factors contributed to this genetic variation?

A - Non-disjunction and mitosis.

B - Cytokinesis and cloning.

C - Crossing over and independent assortment.

D - Asexual reproduction and binary fission.

C - Crossing Over

Explanation:

Crossing over is essentially the gene shuffling and swapping around of genetic information.

A - is false because mitosis describes the building of nonsexual cells. So in terms of genetics, meiosis is the one you're looking for in this scenario.

B - Brothers are not clones.

D - Your parents had to have sex to produce a child. This is not Asexual.

Answer:C