??? .

Resistant.

Explanation:

if they were to possibly be resistant too one of them, then they would have to try something else out too. Plus it's the only one that makes sense.

it would lead to upper respiratory infections and pneumonia.

the flagellates share a facultative mutualist association with termites. mutualism is a biological interaction between individuals of different species, where both benefit from each other. this is called cooperation and it differs from other interactions such as cases of exploitation, such as parasitism, predation. in this interaction called association, both species cooperate and benefit.