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': 'The exocytosis requires which ion \nSelect and explain. \nA. Na+, B. K+, C. Ca+, D. Mg+2', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Substances that move out of cell are transpoed in vesicles and fuse with plama membrane to expel its contents it requires calcium and energy Ref guyton and hall textbook of medical physiology 12/e p18', 'role': 'assistant'}]