LSAT 31, Logical Reasoning II, Q17, LSATHacks

LR Question 17 Explanation, by LSATHacks

QUESTION TEXT: Selena: Asteroid impact on the Earth caused the…

QUESTION TYPE: Necessary Assumption

CONCLUSION: Trent argues that the extinctions must have been caused by something other than an asteroid.

REASONING: The crater was not large enough to have produced all of the dust. And the dinosaurs went extinct over a long period and not just 1-2 years. 

ANALYSIS: Selena wasn’t necessarily arguing that the Yucatan crater was enough to kill the dinosaurs on its own. There could have been other asteroids. Trent is assuming there were no other large asteroids. 

Otherwise, a combination of asteroids might have created enough dust to kill the dinosaurs. 

___________

1. Trent isn’t assuming that every asteroid (even the tiniest ones) would hit only land. It doesn’t affect his argument if asteroids hits the ocean.
2. This doesn’t matter. Trent is arguing that an asteroid did not cause a worldwide extinction of the dinosaurs. He would probably agree that nearby dinosaurs would be killed if an asteroid hit. 
3. Actually Trent is open to the possibility that there is one, single cause. He uses the singular “cause” in his conclusion.
4. It would be ok if there was a slight cooling impact. That might not harm the dinosaurs.
5. CORRECT. It’s possible that multiple asteroid strikes could have created enough dust. And they might have occurred over a long enough period to kill all of the dinosaurs. 

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