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': "Alveoli are kept dry because of \nSelect and explain. \nA. Surfactants, B. Glycorprotiens, C. Buffers Bohr's, D. Effect", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Pulmonary surfactant is a mixture of lipids and proteins which is secreted into the alveolar space by epithelial type II cells. The main function of surfactant is to lower the surface tension at the air/liquid interface within the alveoli of the lung. Ref: guyton and hall textbook of medical physiology 12 edition page number: 317,318,319', 'role': 'assistant'}]