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
[{'content': 'Increase in P50 in oxygenation curve is due to decrease in \nSelect and explain. \nA. PH, B. Oxygen, C. Temperature, D. CO2', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The strength with which oxygen binds to hemoglobin is affected by several factors. These factors shift or reshape the oxyhemoglobin dissociation curve. A rightward shift indicates that the hemoglobin under study has a decreased affinity for oxygen. ... Left shift: higher O2 affinity Ref: guyton and hall textbook of medical physiology 12 edition page number: 354,355,356', 'role': 'assistant'}]