Logical Reasoning

PT16 · S3 · Q18 Because dinosaurs were reptiles, scientists

A free, expert breakdown of this official LSAT Logical Reasoning question.

  • Save & drill this skill — build targeted practice sets from questions like this one

  • Video walkthroughs — watch every question solved step by step

  • 81 official LSATs — as questions, timed sections & full-length tests

Start practicing free

Because dinosaurs were reptiles, scientists once assumed that, like all reptiles alive today, dinosaurs were cold-blooded.

Conclusion

At least some dinosaurs might have been warm-blooded.

Evidence

Dinosaurs were reptiles, and scientists once assumed they were cold-blooded like reptiles today.

Dinosaur fossils were discovered in the northern arctic.

Only warm-blooded animals can withstand arctic winter temperatures, whereas cold-blooded animals would freeze in such cold.

Evaluate

This argument falls into the Explain Curious Fact pattern. The argument presents the discovery of dinosaur fossils in the arctic, which is the Curious Fact. The scientists are questioning how these dinosaurs could survive the cold.

Curious Fact What do you make of these dinosaur fossils in the arctic, where it's too cold for cold-blooded animals like dinosaurs?

Author's Explanation I guess they belonged to some warm-blooded dinosaurs.

Goal

We could weaken the argument by providing an alternate explanation for the arctic fossils or by undermining the plausibility that there were warm-blooded dinosaurs.

18.

Which one of the following, if true, weakens the researchers’ argument?

  1. Today’s reptiles are generally confined

    No Impact

    We already know reptiles are cold-blooded and thus try to avoid cold climates. This doesn't tell us anything useful for figuring out these old dinosaur fossils.

    5% picked this

  2. The fossils show the arctic

    No Impact

    The fact that these dinos seem to have been "way smaller" doesn't seem to provide an alternate explanation for how dinosaurs could survive the arctic winter, nor does it seem to provide a way to say "it's implausible that they were warm blooded dinosaurs".

    5% picked this

  3. The arctic dinosaur fossils were

    Opposite (if anything)

    One potential alternate explanation for the dino fossils is that the Arctic area where the fossils were found wasn't actually cold back in the time of the dinosaurs. We wouldn't need to assume that dinos were warm-blooded if that area were just warmer than it is now. But the presence of plants able to withstand extreme cold makes it seem like the arctic WAS still wicked cold. So that would strengthen the argument, if anything.

    18% picked this

  4. Correct

    The number of fossils found

    Why this is right

    This provides an alternate explanation for the fossils in the arctic. They didn't belong to warm-blooded dinosaurs who lived there all year and survived the frigid winters. They belonged to regular cold-blooded dinosaurs who migrated through the arctic circle during its warmer months. Some dinosaurs would naturally die along the way, so that's how their fossils could end up in that habitat.

    Skill tested: Weaken · how this choice captures the argument's function is the move to repeat next time.

    66% picked this

  5. Experts on prehistoric climatic conditions

    Opposite Impact

    Like with (B), this helps reassure us that the arctic WAS in fact still butt cold back in the day of the dinosaurs, which helps the author. It rules out the potential alternate explanation that we found dino fossils in the arctic because the arctic was actually pretty warm back in the day.

    6% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill
LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free