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The Endowment for Human Development
The Endowment for Human Development
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Slideshow: The Developing Brain

The 4-Week Embryo

#368, Slide 4 of 21

3 weeks, 4 days

From The Biology of Prenatal Development.Buy Now

Label Key:

1. brain
2. body cavities
3. somites
4. tail
All ages referenced to fertilization, not last menstrual period.
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