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': 'Which of the following is the cause of nonshivering thermogenesis in adults? \nSelect and explain. \nA. Noradrenaline, B. Thyroid hormone, C. Muscle metabolism, D. Brown fat between the shoulders', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Nonshivering thermogenesis refers to increase in metabolic rate that is not a result of muscle activity. It appears to be elicited through sympathetic stimulation and circulating catecholamines. Epinephrine and norepinephrine which are released increases metabolic activity and heat generation. Ref: Guyton and Hall - Textbook of Medical Physiology, 10th Edition, Pages 821, 828-829; Medical Physiology: Principles for Clinical Medicine By Rodney A. Rhoades, 4th Edition, Page 568; Fundamentals of Human Physiology By Lauralee Sherwood, Page 489', 'role': 'assistant'}]