Answer: Mostly due to alleles.
Explanation: ...
Answer:
I think the answer is A sexual reproduction results in more time to produce organisms than asexual reproduction.
Geological change will not cause a mass extinction, because it happens on a too big scale - on the scale of millions of years. During such long time, it is more likely that other causes will influence the survival of extinction of species, such as climate change or environmental disasters, and even if there is a small influence, it would not be significant next to other causes.
