Answer: -embryology
Step-by-step explanation:
Comparative embryology is the field of embryology. It deals with the study and comparision of the development, morphology, anatomy, physiology and genetic make of embryos belonging to different species. It also help in determining the evolutionary relatedness of the embryos of the previously existing species and present day organisms on the basis of the similarities and differences in the embryo features. All embryos pass through the stage of few to multiple celled zygotes. The differentiation of the zygote results in the clump of cells called as morulas then into hollow balls of cells called as blastulas. The differentiation of blastula leads to the creation of organs of the body.