What is the feature that first signals gastrulation?
A)Invagination of cells from the epiblast occurs.
B)Folding of the embryonic disc occurs.
C)The yolk sac disappears.
D)The embryonic disc forms.
E)The primitive streak forms.

Question

Quizplus · Accepted Answer

The primitive streak is a feature that first signals gastrulation. It is formed during the third week of development and marks the beginning of the formation of the three germ layers (endoderm, mesoderm, and ectoderm) that will eventually give rise to all the organs and tissues of the body. The primitive streak is a groove on the surface of the embryonic disc, and it is the site where cells begin to migrate inward and differentiate into the different germ layers.

What Is the Feature That First Signals Gastrulation