PT 47 S2 Q22

Until recently, biologists were unable to explain the fact that pathogens—disease-causing ... ...

The examples of diphtheria and tuberculosis bacteria provide the most support for which one of the following conclusions about the dangerousness of pathogens?
(A) The most dangerous pathogens are those with the shortest life spans outside a host.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Practice Set: Science & Technology Mix 1