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: Physiology
Hyperbaric oxygen is dangerous because it: 
Select and explain. 
A. Decreases displacement of 02 from kHb, B. Decreases respiratory drive, C. Enzyme damage, D. Is toxic to tissures
D: Is toxic to tissures
Answer: D: Is toxic to tissures 
Explanation: D i.e. Is toxic to tissuesDecreased cerebral blood flow due to cerebral vasoconstriction caused by high 02 tension is its protective effectQ (not toxic). Which protects brain from free radicle injury.