What are the critical periods in prenatal development

I. Human Developmental Stages (19A) A. :Zygote->Morula->Blastocyst->Gastrulation->Embryo->Fetus->Adult->gametes* * Gametes enable the life cycle to begin again – the egg and sperm have the unique quality that they can reverse the partial differentiation they have done and begin the cycle again; egg and sperm are a unique type of ... ................
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