#22 - Scientists once believed that the oversized head, long

[Administrator]

Please post below with any questions!

[Ceci]

Hi,

Could you please explain why answer choice B is correct and why answer choices A and D are incorrect?

Thank you!

[Jonathan Evans]

Complete Question Explanation

Evaluate the Argument. The correct answer choice is (B)

A "minor" question type, Evaluate the Argument questions actually give you an excellent opportunity to test your skill with Strengthen and Weaken scenarios. First identify the claim that one must abandon the belief that the T. Rex's defining characteristics developed in response to its great size and weight. Next remark the evidence offered to back up this claim: to wit, an earlier, dramatically smaller dinosaur shares these characteristics. Incidentally, this argument continues the long and storied LSAT tradition of dinosaur problems and passages.

In your analysis, consider how well the evidence offered backs up the claim. What do we know? What don't we know? What is the conclusion substantively about? The claim contradicted by the conclusion is that the features of the T. Rex developed in response to its large size. What might be helpful to know whether or not these features actually developed in response to T. Rex's size or for some other reason? Perform the Variance Test™ as needed.

Answer choice (A): This choice actually asks a question to which we already know the answer. According to the stimulus this dinosaur had the features characteristic of T. Rex but was a smaller size. Whether the ratio was a precise match or not will not substantively address the validity of the conclusion because we cannot deviate very far from the fact that regardless of whether the ratio is exact, according to the premises we will always be in the ballpark.

Answer choice (B): This is the correct answer choice. Consider both sides of this possibility. What if the specimen found was of a juvenile, not fully developed dinosaur? The features characteristic of the T. Rex may have developed in this dinosaur in response to the needs of its adult, fully grown size but been present in its earlier state (strengthen). If, on the other hand, the specimen represents a fully grown dinosaur, then some other mechanism must be introduced to account for the presence of these features (weaken).

Answer choice (C): This choice is irrelevant. Irrespective of whether T. Rex was or wasn't the largest prehistoric predator (fun fact, it wasn't—that honor currently goes to Spinosaurus aegyptiacus), this information would do nothing to help or hurt the validity of our conclusion.

Answer choice (D): This attractive answer becomes evidently wrong upon performing the Variance Test™. What if the dinosaur had been related to the T. Rex? Wouldn't really make a difference. This information would still leave unresolved the central issue of whether the characteristics in question were in some respect an adaptation to large size. If the dinosaur is not related to T. Rex, we are still left in the dark about this crucial issue.

Answer choice (E): This choice confuses the issue by perhaps prompting test-takers to misunderstand the stimulus to imply that the characteristics in question were in some sense an adaptation not to the size of the dinosaur with these features but rather to their prey. It is a kind of Shell Game™ answer that preys on (sorry) the test-taker's fatigue once he or she has made it all the way to answer choice (E) and perhaps forgotten what the question had to do with in the first place!

[Kristina Moen]

Hi Ceci,

Does Jonathan's explanation answer your question adequately? If not, you can let us know your thought process on this question, and we will do our best to answer!

[lumosfawkes]

Hi!

I see why B works, but I'm not completely convinced about why A is incorrect. If the ratio of the earlier dinosaur's head size to its body was "the same as that for T. rex" then couldn't it be that, like the t-rex, the earlier dinosaur developed these strange proportions in order to accommodate its size and weight? Even though it's not the same size as the t-rex, it still has the same strange proportions and (presumably) strain on its body because of these proportions. This seems relevant to the argument because it allows the scientists' belief to stand. Though, if the scientists posited that t-rex was the first dinosour to develop this adaptation, then that would weaken the argument. Either way, this still seems like a relevant consideration to me. Could I get your feedback on this? Thanks!

[AthenaDalton]

Hi fawkes,

Answer choice (A) would be a good answer if the small T-rex had the same proportions in terms of both size and weight to the giant T-rex, but we're told in the stimulus that this isn't the case.

The small T-rex discovered was one-fifth the size and one-hundredth the weight. This means that even though the body proportions were just like a miniaturized T-rex on a 1:5 scale, the T-rex was much, much lighter than the real thing (a 1:100) scale.

I hope that makes sense. Good luck studying!

Athena Dalton

[wrjackson1]

Hi I was hoping to give my take on this problem for some feedback.

The conclusion is rejecting the idea that oversized proportions are due to stabilizing the size and weight of the T-rex, backed by the evidence that an earlier dinosaur is has the same characteristics, but doesn't weigh enough for the oversized head and stuff to be necessary.

So, we should be looking for a binary answer that could either streghten or weaken the relevance of the earlier dinosaur fossil to the T-rex. Because of that, answer choice A is incorrect. It could stregthen the arugment by saying that the earlier dinosaur had the proportions for an alternative reason. But, the alternative (they aren't the EXACT same size) doesn't weaken beacuse we already know they have similar characteristics.

[Jennifer Janowsky]

Wrjackson1,

You're right that you're looking for the choice that, when answered, would make or break the following conclusion: Tyrannosaurus rex proportions developed because of their great size and weight.

Choice (A) isn't actually as helpful a question as it initially appears. If the ratio is the same, it would help a little, but the fact is already something the argument has implied. And if it isn't true and the proportions are not exact, we still know that they're close! Therefore, it's not a very powerful option.

However, choice (B) highlights a major gap in the argument: We don't know that the earlier dinosaur is full sized. If it is fully grown, that would indicate the conclusion seems incorrect. But it being a baby would perfectly explain its traits and its lack of size, making the conclusion correct.

So, in summary, you're looking for the answer choice that is the most powerful at both strengthening and weakening the conclusion!

[1month2go]

I initially chose D but after reading your explanation I do see what that was incorrect. When I first read the stimulus B was the first question that popped into my head, but I thought that that answer was too easy/obvious to be correct. Could you explain how to arrive at B as the correct answer aside from process of elimination?

Thanks!

[Cowboys1118]

Wrjackson1,

You're right that you're looking for the choice that, when answered, would make or break the following conclusion: Tyrannosaurus rex proportions developed because of their great size and weight.

This would not affect the decision between the answer choices, but isn't the conclusion of the stimulus that the belief is in fact false that T-Rex proportions developed proportions because of their great size and weight?