Oxygen supply refers to the availability and delivery of oxygen, a vital gas for sustaining life. It is essential for cellular respiration, a process that allows organisms, including humans, to convert food into energy. Oxygen is primarily obtained from the atmosphere, where it makes up about 21% of the air we breathe. In medical settings, oxygen supply can also refer to the provision of supplemental oxygen to patients who have difficulty breathing. This is often delivered through devices like oxygen masks or nasal cannulas. Ensuring a steady oxygen supply is crucial for maintaining health and supporting recovery in various medical conditions.