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: Unknown
[{'content': 'Mucopolysaccharides are \nSelect and explain. \nA. Homopolysaccharides, B. Heteropolysaccharides, C. Proteins, D. Amino acids.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Mucopolysaccharides (commonly known as glycosaminoglycans) are heteropolysaccharides composed of sugar derivatives (mainly amino sugars and uronic acids). The important mucopolysaccharides include hyaluronic acid, heparin, chondroitin sulfate, dermatan sulfate and keratan sulfate.\nHyaluronic acid is the ground substance of synovial fluid of joints. It serves as lubricants and shock absorbent in joints.', 'role': 'assistant'}]