PARENTING

Cleavage – early cell division of a zygote (Fig 29.2 & 29.5) cells become progressively smaller. blastomeres - cells produced by cleavage. 1st cleavage (30 hours) produces 2 blastomeres (2 cell embryo) 2nd cleavage (Day 2) produces 4 cell embryo. 16 cell embryo (Day 3) morula (Day 4) - solid mass of more than 16 cells ................
................