Which of the following lists only includes components of the endocrine system?

These organs are part of the digestive system, not the endocrine system. They are responsible for the mechanical and chemical breakdown of food, nutrient absorption, and waste elimination. While they may produce some hormones related to digestion, they are not classified as endocrine glands.

This choice includes structures that are part of the musculoskeletal system, which provide support, movement, and stability to the body. They do not produce or secrete hormones, and thus are not related to the endocrine system.

These components belong to the nervous system, which is responsible for transmitting signals throughout the body and coordinating responses. While the nervous system can interact with the endocrine system, its components are not part of the endocrine system itself.