Which organisms would most likely be present on the bottom or closest to the actual surface of a complex microbial biofilm?

Question

Quizplus · Accepted Answer

Anaerobic sulfate-reducing bacteria are commonly found in the bottom layer of complex microbial biofilms due to their ability to thrive in oxygen-deprived environments. They are also able to break down complex organic matter, making them important players in the decomposition process of biofilms.

Which Organisms Would Most Likely Be Present on the Bottom