What is the focus of cosmetology?

Cosmetology is the study and practice of improving and enhancing one's appearance. It focuses on the care and maintenance of skin, nails, and hair through various techniques, products, and treatments. Option A, the study of the universe, has no relation to cosmetology and is incorrect. Option C, the study of medicines, also does not pertain to cosmetology, which is focused on enhancing and beautifying appearance rather than treating medical conditions. Option D, engineering new technologies, is also incorrect as it does not involve the practice of cosmetology or the improvement of one's appearance.