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': 'What are the major functions of "I" cells? \nSelect and explain. \nA. Reabsorb potassium ion., B. Secrete potassium ion., C. Excrete potassium ion., D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Reabsorb potassium ion.REABSORPTION IN LATE DISTAL TUBULE:Functionally similar to coical collecting tubule.Facultative type:Reabsorption of solutes/water depends on water/electrolyte balance.Hence, "Facultative type" of absorption.Cells involved in reabsopion:Principal (P) cells.Intercalated (I) cells.FUNCTIONS OF \'I\' CELLS:Reabsorb potassium ion.Secrete hydrogen ions into tubular lumen.', 'role': 'assistant'}]