在所有有性生殖的c囊胚和原肠胚oelomates, there are four main stages of embryogenesis, namely; fertilization, cleavage, gastrulation, and organogenesis. Fertilization is the fusion of haploid male and female gametes to form a diploid zygote. Zygote is the new cell, which is also known as fertilized ovum. In the process of cleavage, the […]