In a frog embryo, gastrulation ________.
A) produces a blastocoel
B) occurs prior to cleavage
C) is impossible because of the large amount of yolk in the ovum
D) proceeds as cells roll over the lip of the blastopore
E) occurs within the inner cell mass that is embedded in the large amount of yolk

Question

Quizplus · Accepted Answer

In a frog embryo, gastrulation proceeds as cells roll over the lip of the blastopore. This forms the three germ layers that will give rise to all the tissues and organs of the developing organism. Gastrulation occurs after cleavage and is possible despite the large amount of yolk in the ovum because of the process of involution, in which cells move from the surface of the embryo toward the interior.

In a Frog Embryo, Gastrulation ________