Same boat here, i read a post that says all the bio questions come from the Campbells text book specifically. My theory is that there isn't any better study guide if that's true. I will read a couple sections out of Cliffs, then while i eat lunch i will run through 3-4 practice tests (40Q's each) on the same subject. I do pretty good on them but every answer is explained well so it's good review. I took the first exam in the back of the Cliffs book and only missed a couple so it seems to be working.