This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
Which of the following is not derivative of mesoderm ? 
Select and explain. 
A. Ureter, B. Gall bladder, C. Uterus, D. Epididymis
B: Gall bladder
Answer: B: Gall bladder 
Explanation: None