A. What is the organ indicated by the green star?

A. What is the organ indicated by the green star? 

B. Using anatomical terms (proximal, distal, etc.), describe the position of the organ with green star in relation to surrounding structures. (Eg. the liver is distal to the heart)

C. Describe the contributions of ectoderm, mesoderm and endoderm to any  organ/structure observable in the image above