The structure at the arrow labeled “B” encloses a region known as the ________________.

The hormone made at pointer B is antagonistic to what other hormone?

Identify the structure indicated by “C” 

Properly identify the area labeled  2

Identify the structure indicated by “B”

List one body structure that the embryonic germ layer at “A” (white) gives rise to.

Name the cell indicated by arrow “B” 

 Identify the specific tubes at letter B.

Identify the embryonic germ layer (green) at “B”.  

Identify the specific substance contained in letter E.