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
[{'content': 'Which of the following is seen in high altitude climbersa) Hyperventilationb)  Decreased PaCO2c)  Pulmonary edemad)  Hypertensione) Bradycardia \nSelect and explain. \nA. ab, B. abc, C. acd, D. bcd', 'role': 'user'}, {'content': 'Answer: B \nExplanation: At high altitude, there can be acute changes and changes due to acclimatization.\n-\xa0\xa0Acute mountain sickness\n\nDyspnoea, dizziness, tiredness, tachycardia, palpitation, nausea, vomiting etc.\nAt higher altitudes- pulmonary oedema and cerebral oedema may occur.\n\n- Acclimatization changes\n\nHyperventilation leading to respiratory alkalosis\nIncreased 2,3DPG- Hb-O2 dissociation curve shifts to right.\nIncreased erythropoietin leading to absolute polycythemia with increased red cell mass.\nIncreased renal excretion of bicarbonate\nIncreased tissue vascularity\nIncreased oxidative metabolism\nIncreased diffusion capacity of the lung\u200b\nIncreased myoglobin', 'role': 'assistant'}]