The Primitive Streak in a Bird is the Functional Equivalent

Question

The primitive streak in a bird is the functional equivalent of
A)the lip of the blastopore in the frog.
B)the archenteron in a frog.
C)polar bodies in a sea urchin.
D)the notochord in a mammal.
E)neural crest cells in a mammal.

Accepted Answer

The primitive streak in a bird is the functional equivalent of the lip of the blastopore in a frog. Both structures mark the site of gastrulation and play a role in organizing the embryo's body plan. The archenteron in a frog is the cavity formed during gastrulation and is not equivalent to the primitive streak. The polar bodies in a sea urchin are small cells that are formed during oogenesis and are not related to gastrulation. The notochord and neural crest cells are structures specific to vertebrates and are not directly related to the primitive streak.