Overgrowth of algae which produces toxins can be caused by
the water's temperature dropping quickly
too much oxygen in the water
not enough nitrogen in the water
nitrogen runoff from the use of fertilizers near the water

because the light is a great source of energy for the plants to survive. (i hope this )

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).

true is the

i believe it would be c: tons.