Question

what is a microaerophile?
o an aerobic bacterium that requires oxygen at a concentration less than that in the atmosphere
o a bacterium that can use oxygen if present but prefers anaerobic mechanisms of metabolism
o a bacterium that requires carbon dioxide in higher levels than the atmosphere

Explanation:

An aerotolerant anaerobe can survive in the presence of oxygen but does not use it for growth. A microaerophile requires oxygen but at a lower concentration than in the atmosphere. A facultative anaerobe can use oxygen if present but prefers anaerobic metabolism. A capnophile requires higher levels of carbon dioxide.

Answer:

an aerobic bacterium that requires oxygen at a concentration less than that in the atmosphere