Which of the following correctly defines an endangered species?

a species that has disappeared entirely
an organism brought to a place where it has not lived before
a species in danger of extinction
a plant growing on public land

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).