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 analogous to the lip of the blastopore in a frog. This is because birds and frogs both undergo gastrulation, during which the cells of the blastula rearrange themselves to form three germ layers, and a primitive streak or lip of the blastopore is an important part of this process.