Which system includes the brain, spinal cord, and nerves?

The nervous system is the correct answer because it encompasses the brain, spinal cord, and nerves, which are all integral components involved in processing and transmitting information throughout the body. The brain serves as the control center, processing sensory information and coordinating responses. The spinal cord facilitates communication between the brain and the rest of the body, while the peripheral nerves extend from the spinal cord to various parts of the body, allowing signals to be sent and received.

In contrast, the endocrine system primarily involves glands that secrete hormones into the bloodstream to regulate bodily functions. The digestive system is concerned with the breakdown and absorption of food, involving organs such as the stomach and intestines. The respiratory system focuses on the exchange of gases, primarily involving the lungs and airways. Each of these systems has distinct functions that do not include the processing and transmission of information like the nervous system does.