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': 'Axillary hair growth is caused by? \nSelect and explain. \nA. Testosterone, B. Estrogen, C. Prolactin, D. Estrogen in women and androgens in man', 'role': 'user'}, {'content': "Answer: A \nExplanation: Testosterone REF: Ganong's 22nd ed p. 430 Secondary sexual hair production in both man and woman is under control of androgens", 'role': 'assistant'}]