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': 'The blood-air barrier consists of all of the following Except \nSelect and explain. \nA. Alveolar pores, B. A layer of surfactant, C. Type I alveolar cell cytoplasm, D. Fused basal lamina of alveolar and endothelial cells', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Alveolar pores connect neighboring alveoli and function in equalizing pressure in the alveoli and enable collateral circulation of air. They do not constitute pa of the blood-air barrier.', 'role': 'assistant'}]