Question

The human respiratory system breathes atmosphere into the lungs. The concentration of oxygen in the atmosphere is higher than that of blood. The oxygen therefore flows into the bloodstream down its concentration gradient through the cell membranes of the lung cells and blood cells. This process is defined as

Answer 1

Answer:gaseous exchange

Answer 2

simple diffusion

Step-by-step explanation:

simple diffusion is responsible for exchange of gases between alveoli and blood. oxygen flows from alveoli to blood and CO₂ flows from blood to alveoli on the principle of simple diffusion