Why is E correct? Why is D incorrect?

Same question here?

I'd also like to know why E is correct, thanks

Hi I am not an instructor and I got this question wrong too. But I understand why it is wrong now. The author is using the known temperature tolerances of the existing beetle species to determine the maximum summer temperature that could have existed at that place and period 22000 years ago. Thus, he temperature tolerances of the beetle species must be assumed to have not varied significantly during the 22,000–year period for the inference to be valid. If the same beetle species tolerated a temperature now that is completely different by the same beetle species 22000, then we cannot use the temperature tolerated by the current beetle species to infer anything about the temperature tolerated by the same beetle species 22000 years as the two temperatures are very different. Thus, E gives us the assumption for the research of using current beetle species temperature to deduce old beetle species temperature to be considered valid, that is, E states: The temperature tolerances of the beetle species did not change significantly during the 22,000–year period. With that assumption, we can safely use the temperature tolerance of beetle species now to infer the temperature tolerance of beetles species 2200 years ago and even infer the maximum summer temperature that could have existed at that place and period 22000 years based on the temperature tolerated by beetle species 2200 years ago. Thank you and please correct me if I am wrong.