You are presented with the question "Electron transport requires which of the following?" and the following answer choices: 
- electron microscope
 - sodium
 - Energy.
 - Oxygen
 - fission
 - warmth
 - flagellum
 - Energy

Now knowing that electron transport is the final stage of aerobic respiration and aerobic respiration occurs only in the presence of oxygen, choose the best answer.


 

    Oxygen     