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: Pathology
[{'content': 'Which of the following is the characteristic of adult respiratory distress syndrome \nSelect and explain. \nA. Diffuse alveolar damage, B. Interstitial tissue inflammation, C. Alveolar exudates, D. Interstitial fibrosis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The disease is mainly caused by a lack of a slippery substance in the lungs called surfactant. This substance helps the lungs fill with air and keeps the air sacs from deflating. Surfactant is present when the lungs are fully developed. Neonatal RDS can also be due to genetic problems with lung development', 'role': 'assistant'}]