Scientists studying fossils of a species of dinosaur found stones in

Question

Scientists studying fossils of a species of dinosaur found stones in the dinosaurs' stomach area. These dinosaurs were vegetarians, but their teeth could not have chewed a sufficient quantity of vegetation well enough to provide nutrition to support their large size. Thus, the stones may have served to help grind up the dinosaurs' food, just as happens with ostriches and some other modern birds. Alternatively the stones may have served as nutritional supplements, supplying minerals not found in vegetation in large enough quantities.

In order to help decide between the two hypotheses for the stones' function, which of the following would it be most useful to know?

(A) Whether the stones had sufficient volume to efficiently grind the vegetation that served as the dinosaurs food
(B) Whether the stones swallowed by ostriches or other modern birds serve to provide any nutritional minerals
(C) Whether stones were found in the stomachs of related species of dinosaurs
(D) Whether any large modern animals typically eat the same sort of vegetation as did these dinosaurs
(E) Whether there is any evidence of the presence of the relevant nutritional minerals in the fossilized bones of these dinosaurs

MartyMurray · Accepted Answer

Explanation

Scientists studying fossils of a species of dinosaur found stones in the dinosaurs' stomach area. These dinosaurs were vegetarians, but their teeth could not have chewed a sufficient quantity of vegetation well enough to provide nutrition to support their large size. Thus, the stones may have served to help grind up the dinosaurs' food, just as happens with ostriches and some other modern birds. Alternatively the stones may have served as nutritional supplements, supplying minerals not found in vegetation in large enough quantities.

We see that the passage presents two possible purposes of the stones:

the stones may have served to help grind up the dinosaurs' food

the stones may have served as nutritional supplements, supplying minerals not found in vegetation in large enough quantities

The support for both hypotheses is the following:

These dinosaurs were vegetarians, but their teeth could not have chewed a sufficient quantity of vegetation well enough to provide nutrition to support their large size.

We see that the reasoning supporting the hypotheses is that, since the dinosaurs' teeth could not have chewed a sufficient quantity of vegetation well enough to provide nutrition to support their large size, the stones must have either helped them grind the vegetation or provided additional nutrition.

In order to help decide between the two hypotheses for the stones' function, which of the following would it be most useful to know?

The answers to the question presented by the correct answer will either weaken the case for one of the hypotheses, strengthen the case for the other, or weaken the case for one while also strengthening the case for the other.

(A) Whether the stones had sufficient volume to efficiently grind the vegetation that served as the dinosaurs food

The answers to the question presened by this choice would help with determining whether the hypothesis that the dinosaurs swallowed the stones for the purpose of grinding their food is correct. After all, if the answer to the question presented by this choice is "Yes," then it is reason to believe that the dinosaurs swallowed the stones for food grinding purposes, and if the answer to this question is "No," then it is reason to believe that the dinosaurs did not swallow the stones for food grinding purposes.

Now, the answers to the question presented by this choice have no direct effect on the case for the hypothesis that the stones may have served as nutritional supplements because, regardless of whether the stones had sufficient volume to efficiently grind the vegetation that served as the dinosaurs food, they could have served as nutritional supplements.

At the same time, if we have the answer to the question presented by this choice, then we do have at least some indication regarding whether the stones served as nutritional supplements. After all, if the stones did not have sufficient volume to efficiently grind the vegetation, then they likely served some other purpose, information making it more likely that the stones served as nutritional supplements.

So, we can see that the answers to the question presented by this choice indicate both whether the stones served to grind the vegatation and whether they served as nutritional supplements, with a Yes answer to the question supporting the vegetation grinding hypothesis over the supplements hypothesis and a No answer supporting the supplements hypothesis over the vegetation grinding hypothesis.

Keep.

(B) Whether the stones swallowed by ostriches or other modern birds serve to provide any nutritional minerals

The correct answer must present a question such that the answers indicate that the stones served ONE OR THE OTHER of the two possible purposes mentioned by the passage.

On the other hand, since we already know that stones swallowed by ostriches help to grind their food, the answer to this question would indicate whether the stones serve BOTH of the two possible purposes mentioned the passage. So, the answers would not indicate what we need them to indicate.

Eliminate.

(C) Whether stones were found in the stomachs of related species of dinosaurs

Notice that, regardless of whether stones were found in the stomachs of other species of dinosaurs, we still would not have information on WHY the stones were there, and the correct answer to this question must be one such that the answers to the question it presents indicate what the purpose of the stones was.

Eliminate.

(D) Whether any large modern animals typically eat the same sort of vegetation as did these dinosaurs

Whether any large modern animals eat the same sort of vegetation as these dinosaurs ate has no bearing on the argument. After all, the point of the argument is not whether they ate the vegetation or whether the vegatation could have provided sufficient nutrition.

The point is that the dinosaurs' teeth were such that they could not have gotten the nutrition they needed by chewing vegetation, so tbey needed to get it in some other way, and we are seeking to determine which way that was.

Now, if this choice were about modern animals using stones to grind food or getting nutrition from stones, the answers to the question it presents might indicate something about why the dinosaurs ate the stones.

As this choice is, though, the answers to the questions it presents have no effect on case for either hypothesis.

Eliminate.

(E) Whether there is any evidence of the presence of the relevant nutritional minerals in the fossilized bones of these dinosaurs

Notice that this choice is about "the fossilized bones" of the dinosaurs. When bones fossilize, their composition changes from what it orignaly was when the animal that had the bones was living.

So, this choice is not about whether the bones of the dinosaurs contained any minerals. It's about whether the bones still have minerals they would have contained while the dinosaurs were living.

After all, the passage says the following:

their teeth could not have chewed a sufficient quantity of vegetation well enough to provide nutrition to support their large size

We see that the passage indicates that the dinosaurs definitely needed nutrition they could not get by chewing vegatation. So, there is no question that, when they were alive, their bodies were using nutrition, such as minerals, that they would have taken in in some way other than chewing vegatation.

Thus, regardless of what the answer to the question presented by this choice is, the dinosaurs could have gotten necessary nutrition from the stones.

So, the answers to the question presented by this choice have no effect on the case for either hypothesis.

Eliminate.

Correct answer:  A

AjiteshArun · Answer

Okay, so it's GMAT instructors and test takers vs. our eventual AI overlords. Let's start. No pressure!

We know that:
 1.  These dinosaurs were vegetarians
 2.  Their teeth could not have chewed enough vegetation (a)  well enough  (b)  to provide nutrition  to support their large size
 3.  There were stones in their stomachs

The argument says that there are two possible reasons for  (3) : "help grind up the dinosaurs' food" or "nutritional supplements, supplying minerals not found in vegetation in large enough quantities".

The task is to figure out which option would help us choose between the { grind food } and { nutritional supplements } hypotheses.

A.  We know that the dinosaurs were vegetarians, so their nutrition doesn't come from other animals. We also know that they were so large that their teeth could not have chewed enough vegetation  well enough .

If the stones were large enough to efficiently ("well enough") grind vegetation, that would  support  the { grind food } hypothesis. Alternatively, if the stones weren't large enough to efficiently grind vegetation, that would  weaken  the { grind food } hypothesis.

B.  The question tells us that as far as modern birds are concerned, the stones do { grind food },  not  { nutritional supplements }. Therefore, by focusing on nutritional minerals, option B tries to link the first hypothesis to the second. Getting an answer to B would tell us whether it's possible for stones to do both { grind food }  and  { nutritional supplements }. It won't, however, help us choose  between  the two hypotheses.

Moreover, we don't know how large these modern birds are, so it's hard to say whether what applies to modern birds also applies to the large vegetarian dinosaurs the question refers to.

C.  In the absence of any further information, knowing only whether stones were found in the stomachs of other dinosaurs won't help us understand what the function of these stones was.

D.  We don't know (a) whether these large modern animals are similarly large, (b) whether they eat only vegetation, (c) whether their teeth can grind food well enough, and (d) whether these modern animals have stones in their stomachs. Therefore, information about whether they eat the same kind of vegetation isn't very useful in helping us choose between the { grind food } and { nutritional supplements } hypotheses.

E.  The question tells us that "the stones may have served as nutritional supplements,  supplying minerals not found in vegetation in  large enough quantities  ". Effectively, we know that vegetation can supply those minerals, just not in large enough quantities. So the presence of " any  evidence" of such minerals isn't as useful as option A in helping us choose between the { grind food } and { nutritional supplements } hypotheses.

If option E had given us information about minerals  not  found (at all) in vegetation, that would have been far more helpful.

katkot · Answer

Google Gemini's Reponse

The most useful information to distinguish between the two hypotheses for the stones' function is:

(E) Whether there is any evidence of the presence of the relevant nutritional minerals in the fossilized bones of these dinosaurs

Here's why:

Option (A) focuses on grinding function, but doesn't address the mineral deficiency hypothesis.
Option (B) explores how stones function in modern birds, not necessarily relevant to this specific dinosaur.
Option (C) studies related species, but it might not clarify if they had similar mineral deficiencies.
Option (D) compares modern animals, but their needs might not reflect those of extinct dinosaurs.
However, (E) directly addresses the mineral deficiency hypothesis. If the relevant minerals aren't present in the fossilized bones, it would weaken the argument for stones supplementing those minerals. If they are present, it wouldn't necessarily confirm the deficiency hypothesis, but it wouldn't contradict it either.

Therefore, by analyzing the fossil bones for relevant minerals, scientists can directly assess the plausibility of the mineral deficiency hypothesis and narrow down the possible explanations for the stones' function.

I was experimenting with Gemini (Google AI thingy) and it also choose E as first choice. Then I prompted it saying that A is the correct choice.  Following is the response:

I apologize, you're correct. Analyzing whether the stones had sufficient volume to grind the vegetation efficiently (option A) would indeed be more useful than analyzing the bones for minerals (option E) in deciding between the grinding and mineral supplement hypotheses. While both options provide valuable information, (A) directly addresses the grinding function, which is the primary alternative explanation to the mineral supplement hypothesis.

Here's a breakdown of why (A) is ultimately more relevant:

The main question is whether the stones helped grind food because the teeth were insufficient. Analyzing the stones' volume and grinding capability directly addresses this question.
While mineral deficiencies are possible, there's no specific reason to suspect them without further evidence. Analyzing the bones for minerals is a broader approach that doesn't directly eliminate the grinding hypothesis.
Finding minerals in the bones wouldn't necessarily confirm a deficiency, as they could have come from other sources. It would only weaken the mineral supplement hypothesis, not definitively disprove it.
Therefore, in this specific scenario, understanding the stones' grinding capacity provides more focused and relevant information to choose between the two hypotheses.

I appreciate you pointing out my mistake and allowing me to learn from it. It's important to consider all perspectives and analyze the problem thoroughly to reach the best conclusion.

Meanwhile ChatGPT's response:

To decide between the two hypotheses for the function of the stones found in the dinosaurs' stomach area, it would be most useful to know:

(C) Whether stones were found in the stomachs of related species of dinosaurs.

This information would help determine if the presence of stones was a common trait among similar species, supporting the idea that they served a particular function related to diet, such as aiding digestion or providing nutritional minerals. If stones were consistently found in the stomachs of related dinosaurs, it would lend support to the idea that they had a specific dietary purpose rather than being a random occurrence or anomaly.

Upon saying that A is the correct option:

My apologies for the oversight. Let's reconsider:

(A) Whether the stones had sufficient volume to efficiently grind the vegetation that served as the dinosaurs' food.

This option directly addresses one of the proposed functions of the stones, which is aiding in the grinding of vegetation. If the stones were large enough to effectively grind the tough vegetation consumed by the dinosaurs, it would support the hypothesis that they served a mechanical purpose in digestion.

So, the correct answer is indeed (A). Thank you for pointing that out!

keshubhturakhia · Answer

MartyMurray

Hello sir

I negated option B on the basis that even if the stones that modern birds ate had nutritional contents, it proves nothing as the stones that dinosaurs were eating could be completely different stones. Would this be a fair argument?

MartyMurray · Answer

That reasoning makes sense as a rationale for eliminating (B). After all, the passage already indicates that the stones may have served as nutritional supplements. So, information indicating that stones serve as supplements in other cases doesn't really make a difference.

Scientists studying fossils of a species of dinosaur found stones in

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Scientists studying fossils of a species of dinosaur found stones in