The right answer is C
This process is called anaerobic respiration. It doesn't need dioxygen to occur (it can happen with or without O2).
Anaerobic respiration is a mechanism in which electrons pass through a chain of transporters whose final acceptor is a mineral substance other than oxygen, unlike aerobic respiration where the final acceptor is dioxygen. The final acceptor may be the nitrate ion (as in the case of Pseudomonas), carbon dioxyde or the sulfate ion.
Some bacteria (Pseudomonas) are able, anaerobically, to reduce nitrates to nitrites and then, depending on the case, to dinitrogen (with the enzyme Nitrate reductase A).
NO3- ==> NO2- ==> N2.
Answer: i belive its A but i may be wrong sorry if i am
Explanation:
A and D are almost entirely solid solid
B - They both use protein channels (I think so at least) they differ because active transports use a pump to leave the cell and it uses atp (cell energy).