17. Identify the specific tubes at letter F.

Identify 1 function of the hormone produced in the area labeled A.

                    20. What is the specific function of the structures contained in region F?

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

20. Identify the specific layer at letter E.

Identify 1 hormone produced by the organ at pointer A.

  What is produced by “A”

20. Identify the specific substance contained in letter E.

The heart _________________.

(Refer to the diagram above FIG.5.) Identify the cell labeled “4.”