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': 'Normal Intrapleural Pressure is Negative because \nSelect and explain. \nA. The chestwall and lungs recoil in opposite directions, B. The surfactant prevents pulmonary collapse, C. Intrapulmonary Pressure is Negative, D. Tranplmonary Pressure is Negative', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. The chest wall and lungs recoil in opposite directions', 'role': 'assistant'}]