Question

genetic variation can arise in a number of different ways. which of these is a way that variation can arise during meiosis
A. fertilization
B. genetic drift
C. crossing over
D. natural selection

Answer 1

@megsrose

Answer 2

@vvvbb

Answer 3

Genetic drift and natural selection are processes associated with evolution. Evolution happens to populations, not individuals, so neither would be applicable to meiosis, which occurs at the level of the individual.

Fertilization is the process by which a sperm and egg combine. By this stage, meiosis has pretty much been completed as far as genetic variation is concerned, because whatever genes the sperm and egg are carrying at that stage aren't going to change.

That means crossing over must be the right answer, and it is - it refers to the process by which homologous pairs of chromosomes swap some of their genes with one another before being separated into daughter cells. This increases genetic variation because it creates new combinations of genes.