I think it would be the option "C"
-I'm not sure-
Diffusion through a permeable membrane moves a substance from an area of high concentration (extracellular fluid, in this case) down its concentration gradient (into the cytoplasm). The passive forms of transport, diffusion and osmosis, move materials of small molecular weight across membranes.
Because lung transplants can easily fail and most of the time lungs are so vulnerable to infection.
Answer:
a large class of mollusks which includes snails, slugs, whelks, and all terrestrial kinds.
Explanation:
hope that helps :D!