AP BIOLOGY

Detailed explanation-1: -Genetic variations can arise from gene variants (also called mutations) or from a normal process in which genetic material is rearranged as a cell is getting ready to divide (known as genetic recombination). Genetic variations that alter gene activity or protein function can introduce different traits in an organism.

Detailed explanation-2: -Genetic recombination occurs naturally in meiosis. Meiosis is the process of cell division that occurs in eukaryotes, such as humans and other mammals, to produce offspring. In this case, it involves crossing-over. What happens is that two chromosomes, one from each parent, pair up with each other.

Detailed explanation-3: -Natural selection acts upon two major sources of genetic variation: mutations and recombination of genes through sexual reproduction. Most mutations do not affect the reproductive fitness of individuals–some may be beneficial, some may be harmful, and many may be neutral.