Cells on the dorsal surface of the two-layered embryonic disc migrate to form a raised groove known as the ________.

Cells on the dorsal surface of the two-layered embryonic disc migrate to form a raised groove known as the ________.

Cells on the dorsal surface of the two-layered embryonic disc migrate to form a raised groove known as the ________. 








A) blastocyst
B) amnion formation
C) germ cell formation
D) primitive streak










Answer: D