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': 'In starvation, nitrogen is carried from muscle to liver and kidney by \nSelect and explain. \nA. Alanine, B. Aspartic acid and Serine, C. Glycine, D. Asparagines', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Transport of alanine from muscle to liver (glucose-alanine cycle) has two functions :-\n\nProviding substrate for gluconeogenesis\nTransport of ammonia (NH4+) to liver for urea synthesis', 'role': 'assistant'}]