This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
Paial pressure of O2 at atmospheric pressure of 760 mm of Hg 
Select and explain. 
A. 76 mm of Hg, B. 160 mm of Hg, C. 120 mm of Hg, D. 140 mm of Hg
B: 160 mm of Hg
Answer: B: 160 mm of Hg 
Explanation: Paial pressure of oxygen at atmospheric pressure is 160 mm HG Ref: guyton and hall textbook of medical physiology 12 edition page number:311,312,313