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
As compared to blood, vitreous humor has high concentration of: 
Select and explain. 
A. Sodium, B. Potassium, C. Glucose, D. Ascorbate
D: Ascorbate
Answer: D: Ascorbate 
Explanation: Ans: D. Ascorbate(Ref Yanoff and Duker 4/e p353)As compared to blood, vitreous humor has high concentration of ascorbate.