What happens to the air we breathe in, once it reaches the lungs?

What happens to the air we breathe in, once it reaches the lungs?
Answer:
When the air breathed in reaches the lungs it enters the alveoli. The alveoli are lined with blood capillaries and exchange of gases occurs. The oxygen from the alveoli is taken up by the capillaries and carbon dioxide from the blood is transferred to alveoli.