2. When a glacier stands still the ice within it A stops flowing and freezes Brecedes and creates a ridge called an end moraine c forms a dark stripe of debris D still flows and carries debris to the end of the glacier

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).