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What is Embryonic period is upto - and explain in detail?
Ans. is 'a' i.e., 8 week o Embryonic period = from fertilization to end of 8 week,o Fetal period = from 9 week on ward,o In prenatal period - following events are seen.Milestones of Prenatal DevelopmentWKDevelopmental events1.Fertilization and implantation: beginning of embryonic period2.Endoderm and ectoderm appear (bilaminar embryo)3.First missed menstrual period; mesoderm appears (trilaminar embryo); somites begin to form4.Neural folds fuse; folding of embryo into human-like shape; arm and leg buds appear; crowm-rump length 4-5 mm5.Lens placodes, primitive mouth, digital rays on hands6.Primitive nose, philtrum, primaty palate; crown-ramp length 21-23 mm7.Eyelids begin8.Ovaries and testes distinguishable9.Fetal period begins; crown-rump length 5 cm; weight 9 g10.External genitals distinguishable20.Usual lower limit of viability; weight 460 g; length 19 cm25Third trimester begins; weight 900 g; length 25 cm28Eyes open; fetus turns head down; weight 1,000 g38.Term