On a class field trip, students swabbed, dug, and dipped samples of life from numerous places around campus. Back in the lab, one of the organisms found was unknown to the professor, or any reference books available, and could not be identified. It came from the edge of a marsh, and the sample smelled of hydrogen sulfide (rotten eggs). The single cells were found to survive only in a container that had sulfate in it, but also had the oxygen removed by burning a candle. This is likely an organism that uses ________ for cellular respiration