When does the embryonic period officially begin?
A)With the onset of cleavage
B)At the time of implantation
C)With the establishment of the three primary germ layers
D)When the umbilical cord becomes functional
E)At fertilization

Question

Quizplus · Accepted Answer

The embryonic period officially begins with the establishment of the three primary germ layers: ectoderm, mesoderm, and endoderm, which occurs during gastrulation.

When Does the Embryonic Period Officially Begin