Answer:
The correct answer is C) Passive transport
Step-by-step explanation:
During the respiration process exchange of gases takes place between lungs and blood. This gas exchange is carried by simple diffusion which is a passive transport. Here gas molecule moves from area of higher concentration to the lower concentration area.
The lung's alveoli are surrounded by blood capillaries in which the concentration of CO2 is high while in alveoli concentration or partial pressure of CO2 is low so CO2 moves from blood to alveoli through diffusion.
In the case of oxygen, the concentration of oxygen is high in alveoli and less in blood inside blood capillaries so oxygen moves from alveoli to blood by diffusion. So the right answer is C.