#20 - Must Be True, Except

[Administrator]

Complete Question Explanation
(See the complete passage discussion here: lsat/viewtopic.php?t=11555)

The correct answer choice is (B)

Since this is an Except question, the four incorrect answer choices will support the biologist’s explanation, and the correct answer will not.

Answer choice (A): This evidence is mentioned, so this choice is one of the four wrong answers that is mentioned in the passage.

Answer choice (B): This is the correct answer choice. There is no discussion of the absence of “carnivores,” only the absence of predators.

Answer choice (C): This is discussed in the third paragraph, so this answer choice should be eliminated.

Answer choice (D): This is alluded to in the third paragraph, so we can safely eliminate this choice from contention as well.

Answer choice (E): This evidence is presented in the final paragraph, so this answer choice must be incorrect.

[bk1111]

Hi, can someone please elaborate on why D is incorrect? The explanation above says this is alluded to in paragraph 3, but I cannot seem to infer this from the paragraph. What do they mean by a need for "a similar explanation"? What exactly is that referring to?

[Adam Tyson]

Hey there bk1111, happy to help! The passage is all about showing that relict behavior could be the reason why pronghorns run so fast, even though they no longer have to since there are no longer any predators fast enough to catch it. This question wants us to pick the one answer choice that does NOT show evidence in support of that idea, and the easiest way to attack an EXCEPT question like this one is to eliminate the wrong answers. Here, any answer that describes evidence that was used to support the relict behavior hypothesis will be incorrect, and whatever is left will be the credited response.

The third paragraph is all about other pronghorn behaviors besides running really fast. Why do they herd? Why do they choose mates based on chases and other speed-based contests? An explanation is needed for those weird behaviors, along with their speed, and relict behavior does the trick. The "similar explanation" is the one, unifying theory that would explain all the weird things pronghorns do, and relict behavior fits all of it. Needing to explain those other behaviors, and relict behavior explaining it all very neatly, lends some additional credence to the theory. So, that evidence helps, and makes D a wrong answer.

[diwil]

Hello,
Thank you in advance for your help.
I have a problem with B being the answer choice (instead of E)
I am wondering why B is an exception for the explanation why pronghorn's speed, since lines 35-36 mention the fact that "pronghorns have nothing to fear from present day carnivores and thus have nothing to gain from herding". This is evidence of relict behavior - before they had carnivores/predators around thus they learned how to run away from them- but now there aren't carnivores, so they don't need to run as fast (although they still do). So, previous presence of predators and the absence of carnivores now explain relict behavior (high speed).
Letter E, on the other hand, talks about relict behavior in "other species". Since it mentions relict behavior in a species other than the pronghorn, it does not support the explanation of the pronghorn speed specifically and directly (it is talking about "other animals"). So, I believe that this should be the best answer choice.
Please, let me know where my reasoning is flawed.
Thank you again,
Diana.

[Adam Tyson]

Happy to help, Diana! The problem with answer B, which makes it the right answer, is that the passage never says that there are no carnivores in North America. What it says is that there are no carnivores that are fast enough to catch a pronghorn! "no North American predator is nearly fast enough to chase it down" (lines 5-6) doesn't mean that there are no North American predators. The pronghorn has no reason to fear present-day carnivores, not because there are none, but because the ones that currently exist are too slow to present a problem for them. Wolves, perhaps, or mountain lions - they exist, but they cannot catch a speedy pronghorn any more than Wile E. Coyote can catch the Roadrunner!

The passage does use evidence of other species - fish and squirrels - to support the hypothesis about the pronghorn. That evidence shows that relict behavior exists in those species, which makes it more plausible that it could also exist in the pronghorn. Basically, the fish and squirrels show that the explanation offered is not unreasonable or unique. That's helpful! It doesn't have to be direct evidence about pronghorns in order for it to help the overall argument. Analogies and comparisons can also help out.