A biologist was studying two indigenous groups of people from different areas of the world. The first population was from equatorial Africa. The second population was from northern Europe. The biologist was studying a gene that affects skin color. The biologist examined the gene in 100 people from each population. She kept track of how many different forms (or alleles) of the gene she found in each population.

the generally accepted parts of modern cell theory include: all known living things are made up of one or more cells. all living cells arise from pre-existing cells by division. the cell is the fundamental unit of structure and function in all living organisms.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).