The giant Chicxulub crater in Mexico provides indisputable evidence

Question

The giant Chicxulub crater in Mexico provides indisputable evidence that a huge asteroid, about six miles across, struck Earth around the time many of the last dinosaur species were becoming extinct. But this catastrophe was probably not responsible for most of these extinctions. Any major asteroid strike kills many organisms in or near the region of the impact, but there is little evidence that such a strike could have a worldwide effect. Indeed, some craters even larger than the Chicxulub crater were made during times in Earth’s history when there were no known extinctions.

Which one of the following, if true, would most weaken the argument?

(A) The vast majority of dinosaur species are known to have gone extinct well before the time of the asteroid impact that produced the Chicxulub crater.

(B) The size of a crater caused by an asteroid striking Earth generally depends on both the size of that asteroid and the force of its impact.

(C) Fossils have been discovered of a number of dinosaurs that clearly died as a result of the asteroid impact that produced the Chicxulub crater.

(D) There is no evidence that any other asteroid of equal size struck Earth at the same time as the asteroid that produced the Chicxulub crater.

(E) During the period immediately before the asteroid that produced the Chicxulub crater struck, most of the world’s dinosaurs lived in or near the region of the asteroid’s impending impact.

LSAT

ApocalyptoRishi · Answer

Why is the answer E? It ratifies the author's argument that an asteroid impact cannot have a worldwide effect.
Because of this ambiguity of thought, I chose C.

taniad · Answer

The giant  Chicxulub crater  in Mexico  provides indisputable evidence that a huge asteroid, about six miles across, struck Earth around the time many of the last dinosaur species were becoming extinct. But this catastrophe was probably not responsible for most of these extinctions. Any major asteroid strike kills many organisms in or near the region of the impact, but there is little evidence that such a strike could have a worldwide effect.  Indeed, some craters even larger than the Chicxulub crater were made during times in Earth’s history when there were no known extinctions.

Summarizing the underlined: Dinosaurs were becoming extinct, however the author argues that Chicxulub asteroid impact could not have wiped out  all the remaining dinosaurs , even though such impacts have killed organisms in the near region.

Need to prove that this particular asteroid impact did cause the death of majority of dinosaurs that resulted in extinction of the species.

(A) The vast majority of dinosaur species are known to have gone extinct well before the time of the asteroid impact that produced the Chicxulub crater.
Mentioned in stimulus already, doesnt add anything to the argument.

(B) The size of a crater caused by an asteroid striking Earth generally depends on both the size of that asteroid and the force of its impact.
Size of crater is irrelevant to the argument.

(C) Fossils have been discovered of a number of dinosaurs that clearly died as a result of the asteroid impact that produced the Chicxulub crater.
Mentioned in stimulus- organisms at or near the impact are killed. Doesn't explain why all the remaining dinosaurs died.

(D) There is no evidence that any other asteroid of equal size struck Earth at the same time as the asteroid that produced the Chicxulub crater.
This would strengthen the argument that something other than asteroid impact caused the extinction.

(E) During the period immediately before the asteroid that produced the Chicxulub crater struck, most of the world’s dinosaurs lived in or near the region of the asteroid’s impending impact.
Weakens the argument- stimulus mentioned organisms living In or near to asteroid impact would be killed off. Stimulus also mentions that dinosaurs were already on the verge of extinction. Hence, if all the remaining dinosaurs lived in the area of this particular impact, it would explain why the species would become extinct in an instant.

madhankumar666 · Answer

The argument says that the asteroid was not the cause of extinction of dinosaurs 
so, the answer choice should says there is a situation when asteroid may be the cause for extinction.
Choices A,B and D are completely out of scope.Choice A doesnot say anything about the asteroid and its effect on dinosaurs,Choice B doesn't say anything about dinosaur, Choice D does not say anything this asteroid, it open to debate that something else might have caused the extinction( to some extent it strengthen)
 CHOICE C:provides evidence number of dinosaurs killed by asteroid. But it doesn't says that all dinosaurs have been killed by the asteroid.
whereas CHOICE E: Shows a scenario when asteroid effects where localised and yet it caused the extinction of dinosaurs.  
SO, E undermines the conclusion.
Hence E is the correct answer

MrudulaL · Answer

GMATNinja  can you pls explain why option C is incorrect

unraveled · Answer

The giant Chicxulub crater in Mexico provides indisputable evidence that a huge asteroid, about six miles across, struck Earth around the time many of the last dinosaur species were becoming extinct. But this catastrophe was probably not responsible for most of these extinctions. Any major asteroid strike kills many organisms in or near the region of the impact, but there is little evidence that such a strike could have a worldwide effect. Indeed, some craters even larger than the Chicxulub crater were made during times in Earth’s history when there were no known extinctions.

Which one of the following, if true, would most weaken the argument?

(A) The vast majority of dinosaur species are known to have  gone extinct well before the time of the asteroid impact  that produced the Chicxulub crater. - WRONG. Irrelevant. No reason to passage further if this option is considered.

(B) The size of a crater caused by an asteroid striking Earth generally depends on both the size of that asteroid and the force of its impact. - WRONG. Then what!! Further assumption/s are required.

(C) Fossils have been discovered of  a number of dinosaurs that clearly died as a result of the asteroid impact  that produced the Chicxulub crater. - WRONG. No problem as such with this one except the fact that we don't know the scale of 'a number of dinosaurs'. Was that number significantly high during that time? OR Was it small? Choice goes in either direction.

(D) There is  no evidence that any other asteroid of equal size struck Earth at the same time  as the asteroid that produced the Chicxulub crater. - WRONG. Sort of a strengthener.

(E) During the period immediately before the asteroid that produced the Chicxulub crater struck,  most of the world’s dinosaurs lived in or near the region of the asteroid’s impending impact . - CORRECT. Weakener.

Another weakener could have been when craters even larger than the Chicxulub crater were made during times in Earth’s history when there were no known extinctions, possibly there were no dinosaurs living on Earth or probably life was not there.
 
Answer E.

GMATNinja · Answer

The author concludes that the asteroid "was probably not responsible for most   extinctions" at the time of its impact.

He/she reaches this conclusion by saying that "there is little evidence that such a strike could have a  worldwide  effect" -- so, even if the asteroid killed off a bunch of dinosaurs in the immediate area of the impact, how can we say that it was responsible for dinos dying in other areas of the globe?

The question asks us to weaken the argument. Here's (C):
 
The author thinks it's totally reasonable that the asteroid killed off dinosaurs  near  the impact site. He/she just doesn't think that we can blame the asteroid for "most" of the dino deaths, because there's no evidence that the asteroid would kill off dinos  far away  from the impact.

(C) tells us that " a number  of dinosaurs that clearly died as a result of the asteroid impact" -- but it doesn't tell us  where  these dinosaurs are. If they were close to the impact area, then (C) would not impact the author's argument at all. If they were really far away, then (C) would provide a nice counterpoint to the argument. But again, we just don't know where the fossils were found.

Because (C) doesn't tell us the location of the fossils, it doesn't weaken the argument.

(C) is out.

Here's (E):
 
Bingo. The author doesn't think we can say that "most" of the dinosaurs died because of the asteroid. But what if most of the dinos lived really close to the impact zone? That would kill the author's reasoning.

(D) is the correct answer.

I hope that helps!

VerbalBot · Answer

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The giant Chicxulub crater in Mexico provides indisputable evidence

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