Thanks everyone.

First of all, I have to say that writing my own explanations (like you all advised) for why the right answer is right & the wrong answers are wrong has really made
think and do things differently this time around. It's definitely a lot harder to do than just reading Kaplan's explanations.
Ugh....tell me there's still some logical reasoning hope for me in these 2 months I have left.
Here's the question:By examining fossilized beetles, a research team has produced the most detailed description yet of temperatures in Britain over the past 22,000 years. Fossils of species that still exist were selected and dated. When individuals of several species found in the same place were found to date to the same period, the known temperature tolerances of the existing beetle species were used to determine the maximum summer temperature that could have existed at that place & period.
The procedure of the researchers assumes which one of the following?(A) Beetles can tolerate warm weather better than cold weather.
(B) Fossils of different species found in the same place belonged to different period.
(C) The process of dating is more accurate for beetles than for other oragnisms.
(D) The highest actual summer temperature at a place & period equaled the average of the highest temperatures that could have been tolerated by each of the beetle species found there & dated to that period.
(E) The temperature tolerances of the beetle species did not change significantly during the 22,000-year period.
The answer is E but I chose B & I couldn't even tell you why!

And can someone explain what the 2nd sentence means??