What organ in the body is primarily responsible for supplying oxygen to the blood?

The lungs are primarily responsible for supplying oxygen to the blood through a process known as respiration. When you inhale, air enters the lungs where oxygen is absorbed into the bloodstream. The alveoli, tiny air sacs in the lungs, facilitate this gas exchange; they allow oxygen to diffuse into the blood while carbon dioxide, a waste product, is expelled from the body during exhalation.

This is critical for the body's overall function, as oxygen is necessary for cellular respiration, the process that generates energy for all bodily functions. While the heart, liver, and kidneys play significant roles in circulation, metabolism, and waste removal, respectively, it is the lungs that are specifically designated for gas exchange and oxygenation of the blood.