Problem 7

Background and context

The zygote undergoes three major developmental phases. These are cleavage, gastrulation, and organogenesis. The cleavage forms blastula by mitotic cell division. The blastomeres are unspecialized stem cells that later become specialized tissue. The specialized embryonic tissue is further differentiated to form three germ layers by gastrulation. These germ layers undergo organogenesis which forms organs of the embryo.