0 h 36 m, 21 ene 2020 año - Embryogenesis

Descripción:

As the third week begins, the two discs undergo gastrulation to become a three layered disc. The embryo takes on an oval shape, with a "primitive streak" along the dorsal surface of the epiblast. The endoderm, mesoderm, and ectoderm are created. These different germ layers begin to migrate and give rise to various mature organs and organ systems.

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