This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
The most metabolically active pa in bone is 
Select and explain. 
A. Coical bone, B. Cancellous bone, C. Periosteal surface, D. Endosteal surface
D: Endosteal surface
Answer: D: Endosteal surface 
Explanation: Endosteum is the most metabolically active pa in bone