the initial period of fetal development. the structure of the zygote, blastocyst. infographics. on b

anatomy artificial blastocyst cell chart contraception cycle development diagram egg embryo embryology eps10 female fertile fertility fertilization follicle genetic gynecology health human illustration implantation implanted infertile infertility medical medicine menstrual morula nucleus oocyte ovarian ovary ovulation ovum period pregnancy reproduction reproductive science sperm stage system uterine vector woman zygote