the stages of segmentation of a fertilized ovum

embryo egg development zygote cell vector pregnancy biology 2cell 4cell anatomy blastomeres blastula embryonic cage child conceiving cytoplasm division embryology endoderm female fertility fertilization reproductive seed stage fetus follicle gastrula genes gynecology health human infertility insemination medical medicine microscopic morula natural oocyte ovary ovulation penetrate reproduction fertilized treatment stages segmentation ovum ovum development zygote 2-cell gastrula