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: Biochemistry
[{'content': 'The nitrogen of the body is supplied by: \nSelect and explain. \nA. Triacyl glycerol, B. Proteins, C. Glucose, D. Lipids', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Proteins are polymers of amino acid. Proteins contain\xa0carbon, hydrogen, oxygen and nitrogen as the major\xa0components. Nitrogen is characteristic of protein. On\xa0an average, the nitrogen content of ordinary proteins is 16% by weight.', 'role': 'assistant'}]