Chapter 28 Pregnancy and Development

embryo week 3 – 8 (week 1 – 8) fetus week 9 - birth. pre-embryonic growth. cleavage. mitotic divisions. morula 16 + cells in a ball ~ day 3 100 cells ~ day 4-5 . enter uterus ~ day 4. blastocyst. hollows in center = blastoceole. trophoblast future chorion. inner cell mass future embryonic disc. twins. identical monozygotic twins ................
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