Here's how it works:

1. Breathing: When you breathe in (inhale), air enters your lungs.

2. Gas Exchange: In the lungs, tiny air sacs called alveoli allow oxygen from the inhaled air to pass into the bloodstream.

3. Circulation: The oxygen-rich blood is then transported throughout the body by the circulatory system (heart and blood vessels).

4. Cellular Respiration: Cells in the body use the oxygen to produce energy, a process called cellular respiration.

Let me know if you have any other questions!