This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Embryology, Subject name: Anatomy
Gut tube develops from which germ layer? 
Select and explain. 
A. Endoderm, B. Mesoderm, C. Ectoderm, D. Allantois
A: Endoderm
Answer: A: Endoderm 
Explanation: Ans. is 'a' i.e., Endoderm * The gut is endodermal in origin and is derived from yolk sac.