A primitive streak forms during the early embryonic development of
A) birds, but not frogs or humans.
B) frogs, but not birds or humans.
C) humans, but not birds or frogs.
D) birds and frogs, but not humans.
E) humans and birds, but not frogs.

Question

Quizplus · Accepted Answer

The primitive streak is a structure that forms during the early development of amniotes, which include birds and mammals (such as humans), but not amphibians like frogs. It is crucial for the initiation of gastrulation, establishing the body plan of the embryo.

A Primitive Streak Forms During the Early Embryonic Development of