Is there any reason that mitosis could not occur in a cell whose genome is haploid?

No, there's no reason at all. mitosis can occur in any type of cell. The fundamental purpose of mitosis is to create identical cells. So, depending on the organism like plants or protist mitosis could even be involved in the production of gametes. In animals mitosis is a cell division that is mostly used for growth or tissue repair.

the fossil record provides evidence of a common ancestor to many species.

answer: b

coz red blood cells marrow and circulates the body for 120 days.