embryo development ovulation, fertilization, and the initial stages of growth in detail

embryo development ovulation fertilization initial stages growth detail reproductive process cell division zygote formation blastocyst implantation differentiation germ layers embryonic cellular proliferation developmental biology maternal health follicular phase cleavage morula stage mass trophectoderm gastrulation neurulation organogenesis factors period placental amniotic sac umbilical cord pregnancy hormones nutrition viability prenatal care genetic predispositions environmental influences assisted technologies