The giant Chicxulub crater in Mexico provides indisputable evidence that a huge asteroid, about six miles across, str...

meisen on May 31, 2018


Why is C wrong?

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Christopher on June 6, 2018

@meisen, this is a Weakening Question, so you're looking for information that challenges the logical progression of the question. The short version of the question is that since larger asteroid strikes did not cause global extinctions, there is nothing to suggest that the Chicxulub impact could have caused enough global impact to have caused most of the dinosaur extinctions that happened around the time of the impact.

(C) points to evidence that some dinosaur fossils have been discovered that clearly died from the Chicxulub impact to weaken the argument, but the question anticipates this by saying that such an impact would cause significant death and destruction in the immediate area but not on a global scale. So any dinosaurs in the immediate vicinity would have died, and finding a few fossils that support this would not weaken the larger argument.

(E) is correct because the argument is that the Chicxulub asteroid probably was not responsible for MOST of the dinosaur extinctions at the time because its environmental impact would have been localized. However, if MOST of the dinosaurs that were still alive at the time were living in the impact zone, then the Chicxulub asteroid could have caused the death of all of the dinosaurs in the immediate vicinity therefore precipitating MOST of the dinosaur extinctions at that time.

Make sense?

Julie-V on August 24, 2019

I chose (E) but would love an explanation as to why (B) would be incorrect. Thanks!

Irina on August 25, 2019


(B) has no impact on the validity of the conclusion. The argument tells us that a giant crater is unlikely to have a worldwide impact resulting in dinosaur extinction, considering even larger craters date back to times when there were no known extinctions. The fact that the size of a crater depends on the size of the asteroid and the force of its impact is just a general observation and by itself fails to undermine the conclusion that this particular Chicxulub crater is not responsible for most of the extinctions.

Let me know if you have any other questions.