Red Seal Cosmetology Practice Exam

Human hair is primarily made up of the protein keratin, which is composed of carbon, hydrogen, oxygen, nitrogen, and sulfur. Therefore, the correct element order is C-H-O-N-S, making option B the correct answer. Option A is incorrect because the elements are not listed in the correct order. Option C is incorrect because it has an extra "S" at the end. Option D is incorrect because it has "HON" which is not in the correct order.