New York State Cosmetology Practice Exam

Living cells are composed of various substances, but the primary substance they are composed of is protoplasm. Protoplasm is a collective term used to describe all the living components of a cell, including the cytoplasm (gel-like substance surrounding the organelles), nucleoplasm (fluid inside the nucleus), and other cell organelles. Therefore, options B, C, and D are incorrect because they do not encompass all the essential components of a cell as protoplasm does.