Answer:
Gas exchange
Step-by-step explanation:
Gas exchange can be described as the movement of gases in opposing direction across an interface. In humans and other animals with lungs, gas exchange occur as a process of respiration.
Oxygen is inhaled into the lung. In the alveoli of the lung, the inhaled oxygen diffuses into the bloodstream within the blood capillaries. Carbon dioxide in the blood travelling within the blood capillaries diffuses the other way (into the alveoli)