Final answer:
When S. aureus undergoes anaerobic respiration, it uses carbon dioxide as the final electron acceptor.
Step-by-step explanation:
When S. aureus undergoes anaerobic respiration, it does not use oxygen as the final electron acceptor. Instead, certain prokaryotes, including some bacteria like S. aureus, use an inorganic molecule as the final electron acceptor in a process called anaerobic respiration. For example, archaeans called methanogens use carbon dioxide (CO2) to oxidize NADH, producing methane. Therefore, the answer is 2) Carbon dioxide.