Variations within a species are most likely the result of:
A. synapses and disjunction.
B. overpopulation and recombination.
C. mitosis and asexual reproduction.
D. mutations and sexual reproduction.
Mutations increase variety in a species and sexual reproduction increases variety because of crossing over, two different parents combining genes, and because of the way the chromosomes line up at the equator during metaphase I of meiosis.