In a Frog Embryo, Gastrulation

Question

In a frog embryo, gastrulation
A) produces a blastocoel displaced into the animal hemisphere.
B) occurs along the primitive streak in the animal hemisphere.
C) is impossible because of the large amount of yolk in the ovum.
D) proceeds by involution 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.

Accepted Answer

In a frog embryo, gastrulation proceeds by involution as cells roll over the lip of the blastopore. This is the process of cells on the dorsal surface migrating inwards and expanding the blastocoel, ultimately forming the three germ layers of the embryo.