Which body system is primarily responsible for supplying the body with oxygen?

The respiratory system is primarily responsible for supplying the body with oxygen. This system includes key structures such as the nose, trachea, bronchi, and lungs, which work together to facilitate the process of breathing. When you inhale, air enters the lungs, where oxygen is exchanged for carbon dioxide in the alveoli, the tiny sacs in the lungs. This oxygen is then transported through the bloodstream to the body's tissues and organs, where it is used for cellular respiration—the process that generates energy.

Although the cardiovascular system is crucial for transporting oxygen throughout the body, it does not gather oxygen; instead, it relies on the respiratory system to provide the oxygen that the blood carries. The muscular system and nervous system serve other vital functions, such as movement and coordination, but they do not directly supply oxygen to the body. Therefore, the respiratory system is correctly identified as the primary system for oxygen supply.