What three noteworthy physical characteristics of corynebacterium xerosis are visible after performing a simple stain?

Simple stains are used for identification of basic shape, approximate size, and arrangement of cells present. So, staining Corynebacterium xerosis you can see it is a diphtheroid organism rod-shaped, straight or slightly curved. Those bacteria group together in a characteristic way, in the form of a "V".

weathering is the answer.

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).