You decide to go on vacation in the mountains, where you are staying in a cabin. Unfortunately, when you turn on the water in the cabin you smell hydrogen sulfide ($$H_2S$$) gas. After some research, you find out that the $$H_2S$$ may be due to the presence of sulfur bacteria living in your pipes. What molecule do these bacteria use as an electron acceptor?
Multiple Choice
$$H_2S$$
$$O_2$$
$$H_2O$$
$$SO_4$$