Gian wrote:
Some say that an asteroid colliding with Earth was responsible for the extinction of the dinosaurs. It is indeed likely that such a collision did occur and that it caused the death of the vast majority of dinosaurs. However, new evidence suggests that perhaps tens of thousands of dinosaurs lived far enough from the point of collision that they were not directly killed by the impact or by the drastic change in temperature when immense dust clouds created by the impact blocked the sun. Some other force must have been responsible for the death of these remaining dinosaurs.
Which of the following, if true, is an assumption made by the author of the above argument?
A. The water supply used by the dinosaurs who survived the asteroid collision and subsequent change in global temperature had not become contaminated by lethal fallout from the collision.
B. A second asteroid impact or some other cosmic event is likely to have killed off the dinosaurs that survived the asteroid impact and global temperature change.
C. At least a few dinosaurs continued to exist for some years after the asteroid collided with Earth.
D. There is another existing theory that does a better job of explaining the extinction of the dinosaurs than the theory involving an asteroid collision with Earth.
E. The change in temperature caused when dust clouds from the asteroid impact blocked the sun could not have lasted for several years.
It is likely that an asteroid collision did occur and caused the death of the vast majority of dinosaurs.
However, new evidence suggests that perhaps many dinosaurs lived far enough that they were not directly killed by the impact or by the drastic change in temperature when dust blocked the sun.
Conclusion: Some other force must have been responsible for the death of these remaining dinosaurs.
The author says that it is likely that a meteor killed majority of dinosaurs but that many dinosaurs lived far enough to not get a direct hit of the impact or the temp change. So, some other "force" (not the asteroid collision) must have been responsible for wiping out the rest.
What is the assumption here?
That some other aspect of asteroid collision which would impact dinosaurs all across the globe is not responsible for extinction.
A. The water supply used by the dinosaurs who survived the asteroid collision and subsequent change in global temperature had not become contaminated by lethal fallout from the collision.
Correct. This gives you a different aspect (water contamination) of asteroid collision that could have impacted far away dinosaurs. This is an assumption.
B. A second asteroid impact or some other cosmic event is likely to have killed off the dinosaurs that survived the asteroid impact and global temperature change.
No assumption about a second asteroid or cosmic event. The author just says "other force". It may not be another cosmic event.
C. At least a few dinosaurs continued to exist for some years after the asteroid collided with Earth.
The immediate problem with this option is "some years". The author doesn't need to assume that some dinosaurs existed for some years. She just says that all were not killed by direct impact. Even if some survived for 2 months after impact, it is enough for her argument. We cannot assume anything about this timeline.
D. There is another existing theory that does a better job of explaining the extinction of the dinosaurs than the theory involving an asteroid collision with Earth.
No such assumption. She says that it is likely that asteroid collision killed majority of dinosaurs. She is looking for an additional explanation to complete the event.
E. The change in temperature caused when dust clouds from the asteroid impact blocked the sun could not have lasted for several years.
No such assumption. We don't know how many years or months or days it lasted and how that impacted dinosaurs in that area and elsewhere.
Answer (A)
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