This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory System, Subject name: Physiology
Arrow shift of the curve is not due to: 
Select and explain. 
A. Increased hydrogen ions, B. Decreased carbon dioxide, C. Increased temperature, D. Increased BPG
B: Decreased carbon dioxide
Answer: B: Decreased carbon dioxide 
Explanation: Ans. (b) Decreased carbon dioxide(Ref: Ganong, 25th ed/p.640)In oxygen dissociation curve, right shift is favored by,AcidosisIncrease in, 3 DPGIncrease in PCO2 Increase in temperature