PT 59 S2 Q21

   Essayist: When the first prehistoric migrations ofhumans ... ...

Which one of the following, if true, most weakens the essayist's argument?
(A) Animals weakened by disease are not only less able to avoid hunters but are also less able to avoid their other predators.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Complete Section: LR-A, Dec. '09 LSAT (PT 59 Sec. 2)