Answer:
Embryonic development includes cleavage, blastulation, implantation, gastrulation and organogenesis.
Explanation:
Zygote undergoes cleavage divisions to form 2-cell, 4-cell and then 8-cell stage. The 8-cell stage then divides further to become a 16-cell stage called morula. It is a solid ball of cells. Morula then transforms into a 32 cell stage called blastocyst. It has a cavity called blastocoel. It is the at this stage the implantation of developing embryo occurs in the endometrium of uterine wall. Blastocyst then undergoes a process of gastrulation to form the gastrula stage which shows the presence of three germ layers i.e. ectoderm, mesoderm and endoderm. Once the germ layers are formed organogenesis begins.
