<span>Isotopes of the same elements differ in their mass number. Isotopes are those elements have the same protons but differs from their neutrons. That is why it differs in their mass number because the mass number is the sum of protons and neutrons.</span>
Answer D. Because the DNA is different
G<span>enes are found in your chromosomes. The correct answer is D.</span>
Nonrandom mating-inbreeding or genetic drift