It's either going to be something on lungs, cells or immuntiy. More specifically cell-mediated and humoral responses or absoprtion in epithelial cells or phospholipid bilayer or maybe phagocytosis. Just guessing. I'd say absorption or specifically the sodium potassium pump may come up. that hasn't really come up has it? I hope it does as I have that **** dooown.
Also for the mitochondria question it says this: Mitochondria produce ATP/release energy; So either is fine tbh.