Where in the Embryo Does Mesoderm First Appear

Question

Where in the embryo does mesoderm first appear?
A) between the cell layers of the inner cell mass
B) within the blastocoele
C) in the chorionic villi
D) above the epiblast
E) around the trophoblast

Accepted Answer

Mesoderm first appears between the cell layers of the inner cell mass during embryonic development. This layer gives rise to many structures including muscles, bones, and the circulatory system.