Which of the following is NOT classified as a major organ system in the body?

The nuclear system is not classified as a major organ system in the body. In anatomical and physiological contexts, the major organ systems recognized include the muscular system, the skeletal system, and the endocrine system, which all play essential roles in maintaining overall health and bodily function.

The muscular system is responsible for movement and maintaining posture, the skeletal system provides structural support and protection for internal organs, and the endocrine system is involved in hormone production and regulation, affecting various physiological processes. In contrast, the nuclear system does not refer to a recognized organ system in human biology. Instead, it may relate to cellular components or nuclear functions within a cell rather than being an organ system that contributes to the overall function of the body.