by bbirdwell Sat Jan 22, 2011 3:35 pm
Just keep the negatives straight and this problem is easier.
Here's what we know:
1. vexone has been used effectively against ALL species in North America
2. in testing Roach Ender, which contains vexone, this fact has been proven
We should eliminate every choice that conflicts with these facts.
(A) conflicts -- it's effective against all species.
(B) conflicts -- ALL of them can be controlled with vexone, and Roach Ender contains vexone.
(C) does not conflict -- it's almost exactly what the argument says.
(D) conflicts -- ALL species have been proven to be controlled.
(E) conflicts -- MORE than 4000 species were tested...
Therefore, (C) is the answer. Does that help?