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': 'Hydrogen ion is eliminated by: September 2005 \nSelect and explain. \nA. Kidney, B. Lungs, C. Liver, D. Stomach', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A: Kidney Cells of proximal and distal tubules secrete hydrogen ions which comes from carbonic acid For each hydrogen ion secreted, one sodium ion and one bicarbonate ion enters the interstitial fluid.', 'role': 'assistant'}]