Embryosis is the formation of an embryo. There are two main steps to this process: blastulation, and gastrolation. To begin, the sperm and egg cell must fuse to form a zygote. The fusion of sperm and egg allow the genetic material to merge, all cells are pluripotent at this point. Next there is clevage, compaction, and differentiation forming the blastocyte. The overall size of the blastocyte is not much bigger than the zygote, due to compaction. There are many more cells in the blastocyte because of clevage, with some differentiation between the inner cell mass and surrounding cells. Gastrolation is the formation of three distinct layers in the blastocyte which will differentiate into different tissues in the bdoy. The top layer is the ectoderm, the middle layer is the mesoderm, and the bottom layer is the endoderm. The ectoderm differentiates into the nervous system and the skin. The mesoderm differentiates into the muscles; the endoderm differentiates into the internal organs. This process is virtually the same for all mamals. The outcome is very different because of the genetic information fused, resulting in a wide range of organisms.
Comments
transition words
I don't think "To begin" is a great transition word to include in scientific writing. Chronological order is usually seen instead.
Avoid words like "next" which
Avoid words like "next" which are more narrative based words. Exposition may be more preferred from the professor
Word Choice
'There are many more cells' is a bit subjective, consider using more explicit word choice.