Answer: Alveoli
Explanation: Alveoli is the air sacs in the lungs through which oxygen and carbon dioxide diffuse into and out of the blood.
Red because it has more volume and more amount of matter
The important point is that the surface area<span> to the </span>volume ratio<span> gets smaller as the </span>cell<span> gets larger. Thus, if the </span>cell<span> grows beyond a certain </span>limit<span>, not enough material will be able to cross the membrane fast enough to accommodate the increased cellular </span>volume<span>.</span>