Which system of the human body is responsible for supplying oxygen?

The respiratory system is crucial for supplying oxygen to the body. It consists of structures such as the lungs, bronchi, and trachea, which work together to facilitate the exchange of gases. When we inhale, oxygen enters the lungs, where it diffuses into the bloodstream. This oxygen is then transported throughout the body to cells that require it for various metabolic processes. Additionally, the respiratory system plays a vital role in removing carbon dioxide, a waste product of metabolism, from the body when we exhale.

While the cardiovascular system also plays an important role in transporting oxygen, it relies on the respiratory system to initially acquire the oxygen from the air. The digestive system is primarily responsible for breaking down food to provide nutrients, and the nervous system regulates bodily functions but does not directly supply oxygen. Therefore, the respiratory system is the correct answer, as it is directly responsible for the intake of oxygen into the body.