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: Ophthalmology
Metabolically most active layer of cornea is: 
Select and explain. 
A. Endothelium, B. Stroma, C. Descemet's membrane, D. Epithelium
D: Epithelium
Answer: D: Epithelium 
Explanation: Ans. Epithelium