This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Principles of Gas Exchange -  Respiratory Membrane, Subject name: Physiology
Effect of fetal hemoglobin on O, dissociation curve- 
Select and explain. 
A. Right Shift, B. Left Shift, C. No effect, D. May be right or left
B: Left Shift
Answer: B: Left Shift 
Explanation: Ans. is 'b' i.e., Left shift Oxveen dissociation curveShifted to rightShifted to lefto Decreased oxygen affinity to hemoglobino Increased P50o Increased oxygen deliveryQ to tissueso Causes;* Decreased pH (Acidosis) Q* Increased temperatureQ* Increased PCO6* Increased 2,3 DPG(BPG)6i) Growth hormone, Androgen, thyroid hormoneii) ExerciseQiii) Tissue hypoxiaQiv) High altitudeQv) AnemiaQvi) Alkalosisvii) Cyanotic CHDviii) Pregnancyix) Chemicals: - InosineQ, Pyruvate. PEP, phosphate* Sickle hemoglobin (HbS) Q.o Increased oxygen affinity to hemoglobinQo Decreased P50o Decrease oxygen delivery Q to tissueso Causes;* Increased pH (alkalosis) Q* Decreased temperatureQ* Decreased PCO2Q* Decreased 2,3 DPG (BPG)Stored bloodQ* Fetal hemoglobin (HbF) Q