Answer: mitosis
Explanation:when an egg is fertilized,it becomes a zygote.the zygote is single-cell and undergoes cleavage.cleavage is the mitotic division of a zygote into smaller cells also called blastomere,which forms a spherical mass.
The type of cleavage is dependent on the different animals and whether yolk is present.
As the zygote continues to grow,organs rudiments forms and organs form afterwards, through mitotic division.
In Mitosis the daughter cell has the same number of chromosomes as the parent cell and it is essential in the increase of the number of cells causing growth in multicellular organisms.
Mitosis also helps to regenerate lost body parts.
