Which system is responsible for controlling all body functions and interactions with the environment?

The nervous system is essential for controlling all body functions and facilitating interactions with the environment. It acts as the body's communication network, transmitting signals between different parts of the body and the outside world. The nervous system processes information received from sensory organs, analyzes it, and initiates appropriate responses, allowing for coordination and regulation of functions such as movement, thought, reflexes, and homeostasis.

In this context, the other systems mentioned play significant roles as well; however, they do not have the overarching control that the nervous system provides. The musculoskeletal system is primarily responsible for movement and structural support, the skin serves as a protective barrier and interacts with the environment through the senses, and the circulatory system is involved in transporting blood and nutrients throughout the body. While important, these systems rely on the nervous system to integrate their functions and respond effectively to environmental stimuli.