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
O2 which is about 21% of inspired air exerts a partial pressure of 
Select and explain. 
A. 160 mmHg, B. 240mmHg, C. 580mmHg, D. 760mmHg
A: 160 mmHg
Answer: A: 160 mmHg 
Explanation: In inspired air, partial pressure of O2- 158mmHg