The correct answer is option d) age of either or both parents.
Explanation:
Genetic variation is the difference in nucleotide sequences between individuals organisms within a particular population. Variation can occur either in germ cells that are sperm and egg or in somatic cells or in both.
Random fertilization of egg and sperm can lead to genetic variation is every germ cell has a different set of chromosomes. Independent assortment of chromosomes is also the same as random fertilization as it is also random. Crossing over of homologous chromosomes is one of a major source of the genetic variation as it forms a new set of chromosomes.
Thus, the correct answer is option D) age of either or both parents.
A because protons make the atom the element it is and the molar mass is made up by the neutrons and protons. The protons must stay the same to keep the same element and electrons hardly have mass so A
