What system is responsible for gas exchange in the body?

The respiratory system is the correct choice because it is specifically designed for the exchange of gases, primarily oxygen and carbon dioxide, between the body and the environment. The process of respiration occurs in the lungs, where oxygen is inhaled and absorbed into the bloodstream, while carbon dioxide is expelled from the blood and exhaled out of the body. This system plays a crucial role in maintaining the body's oxygen levels, which are vital for cellular function and overall metabolic processes.

Other systems mentioned do not partake directly in gas exchange. The digestive system focuses on the processing of food and absorption of nutrients. The nervous system is responsible for transmitting signals throughout the body to coordinate functions but does not directly facilitate gas exchange. The endocrine system utilizes hormones to regulate processes such as growth, metabolism, and mood, but it is not involved in gas exchange either. Thus, the respiratory system is uniquely equipped to manage the essential function of gas exchange.