Twin colts were born from a black mare and a black stallion One colt was black and one was brown. The colts have different traits because their dna contains-

heat a spark and oxygen

answer; the correct answer is (beta)

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).