Final answer:
The intestine has the largest anaerobe-to-aerobe ratio among microbial reservoirs.
Step-by-step explanation:
In terms of anaerobe-to-aerobe ratio, the microbial reservoir with the largest ratio is the intestine.
The intestines have a high number of anaerobic bacteria compared to aerobic bacteria. The anaerobes are able to thrive in the low-oxygen environment of the intestines, whereas aerobes require oxygen to survive.
Examples of anaerobic bacteria in the intestines include Bacteroides and Clostridium species.