#18 - Because dinosaurs were reptiles, scientists once

[maximbasu]

Hello,
I chose A as the correct answer while the correct answer was D.

How is D correct? Couldn't the reptiles just migrate further North? It seemed to me that there was no relation to migrating further North and warm-blooded/ cold-blooded animals.

Thank you, Maxim.

[Clay Cooper]

Hello Maxim,

Thanks for your question.

I too did not see at first why D weakens the researchers' conclusion. On a second look, though, I noticed that we are only told that cold-blooded animals could not survive arctic winters - not that they couldn't survive in the arctic at all. With that in mind, it is plausible that large groups of them, forced to migrate continually in search of food, might move into the region during spring or summer only to die together when winter came.

Thus, D suggests a plausible alternate cause for the bones coming to rest there, and is the best answer.

I hope that helps. Don't be discouraged, I initially missed that subtlety as well.

[hassan66]

After reading the explanation, I can see the nuance in D that lends itself to be true. I initially chose E. Is this wrong because we don't know what the temperatures of the arctic are today? I just assumed that the temperatures are not that cold today which means they would not have been cold then. But this would attack one of the premises right?

[Jonathan Evans]

Hi, Hassan,

Yes, the premises stipulate that "frigid temperatures [...] are characteristic of arctic winters." Therefore we know from a premise that arctic winters are cold. With answer choice (E), we may infer correctly that prehistoric arctic winters were also cold. Since this additional information would in fact corroborate the author's assumption that the prehistoric arctic winters were cold (so the dinosaurs must have been warm blooded), this answer choice is an opposite answer. It strengthens the argument!

[deck1134]

Hi PowerScore,

I hope you are doing well.

I choose answer choice C on this question, though I now see that there is more nuance to D than I had originally thought. My thoughts on (C) were that if plants existed in the artic, it would be possible for other life to exist there even if it lacked warmblooded systems. Is that too much mental gymnastics for this question?

Thanks.

[deck1134]

Just bumping this up!

[onlywinter]

Deck1134,

Answer choice C does not weaken the conclusion, which is that at least some dinosaurs might have been warm-blooded. If anything, it strengthens the argument. If dinosaurs were able to survive alongside plants able to withstand low temperatures, they are more, not less likely, to be warm-blooded.

I chose D because the dinosaurs in question could have wandered to the arctic by accident in order to find food. Once there, they died. This would weaken the idea that they were warm-blooded, which is the idea we want to weaken.