Which system allows the body to take in oxygen and expel carbon dioxide?

The respiratory system is responsible for the process of taking in oxygen and expelling carbon dioxide. It includes the organs and structures involved in breathing, such as the lungs, trachea, and diaphragm. During inhalation, oxygen is drawn into the lungs where it is exchanged for carbon dioxide, a waste product produced by the body's cells. This exchange occurs in the alveoli, tiny air sacs in the lungs, allowing oxygen to enter the bloodstream and be circulated throughout the body.

In contrast, the digestive system focuses on breaking down food and absorbing nutrients, while the circulatory system is responsible for transporting blood, nutrients, and gases throughout the body. The nervous system plays a crucial role in sending signals and coordinating bodily functions, but it does not directly facilitate gas exchange. Understanding these distinctions helps to clarify the specific functions of each body system.