The blue-tipped Puffer is a migratory bird that is found

Question

The blue-tipped Puffer is a migratory bird that is found along the coast of this state in summer months. The Puffers enjoy the seeds of Thomson’s Mulberry trees; because these trees are plenty in the state’s Coastal Park, traditionally many blue-tipped puffers would be found in the park during summer months. Ten years ago, the grey fox was re-introduced into the park, and their number have been thriving. Over that time, we have seen many fewer Puffers in the park during the summer months. Clearly, the Puffers, sensing a potential predator in the fox, are choosing to spend their summers elsewhere.

Which of the following would be the most important to determine in order to evaluate the argument?

(A) What other birds and small mammals the grey fox typically hunts besides the blue-tipped Puffers.
(B) Whether the grey fox eats the fruit of the Thomson’s Mulberry trees.
(C) How the speed of a blue-tipped Puffer during take-off from the ground compares to the speed of a grey fox running
(D) Whether the range of the grey fox within the park extends all the way to the coast.
(E) Whether other coastal areas in the state have seen an increase in the number of blue-tipped Puffers over the last decade.

For a general discussion of Evaluation the Conclusion GMAT CR questions, as well as a complete explanation of this question, see:
https://magoosh.com/gmat/2013/gmat-criti ... onclusion/

Mike :-)

April, 2015:
UPDATE: this question had some problems and has been revised. Please see the revised version here:
https://gmat.magoosh.com/questions/3794

Mike :-)

Show Answer

Official Answer

E

April, 2015 : UPDATE: this question had some problems and has been revised. Please see the revised version here: https://gmat.magoosh.com/questions/3794 Mike :-)

mikemcgarry · Accepted Answer

Nick , You will notice, first of all --- even if the fox eats the fruits , the birds eat the seeds , so there's not necessarily direct competition. This starts to get into outside knowledge, but there are many ecosystems in which some larger animals eat the fruits and smaller animals (birds or rodents) eat the seeds, and those are complementary and independent food systems, not in competition with one another. More to the point, what exactly is the argument we are trying to evaluate? The argument is: the Puffers are choosing to spend their summers elsewhere . Suppose somebody with more evidence came along and told us the answer to (B) --- suppose they told us: yes, absolutely, fox love to eat the fruit of the Thomson’s Mulberry trees --- in fact it's their favorite food ! That's a very clear answer to the question posed in (B) , but even if we knew that, could we decided what happened to the Puffers? Would it mean that the fox, in seeking its favorite food, stumbled on to Puffers and ate them too? Or would it mean the Puffers starved? Or would it mean the Puffers are alive and well somewhere else and are, as the argument suggests, spending their summers elsewhere? Fundamentally, we are trying to answer the question --- what happened to the Puffers, and even having a clear and unambiguous answer to (B) doesn't allow us to have a clear and unambiguous answer to this question. By contrast, with (E) ---if we see the Puffers elsewhere, other coastal areas, then we know exactly what happened to them. That would provide an unambiguous answer to the question posed by the argument. That's always what you are seeking in an "evaluate the argument" question. Does all this make sense? Mike :-)

AMITAGARWAL2 · Answer

between D and E
(D) Whether the range of the grey fox within the park extends all the way to the coast.
if fox are only in park then birds should have not gone from entire coast.... So does not help evaluate the argument.
(E) Whether other coastal areas in the state have seen an increase in the number of blue-tipped Puffers over the last decade.
if other coast have not seen the changes the conclusion is incorrect and but otherwise conclusion is correct. This helps- Correct choice.

SVaidyaraman · Answer

The premise is : Puffers sense a potential predator in Fox
The conclusion is: They choose not to spend the summers where the foxes are i.e., in the coastal park

To evaluate an argument: (i) One needs to evaluate whether the premise is true or (ii) The conclusion follows from the premise

So for this particular argument one needs to find out (i) whether the grey fox is indeed a predator of the puffers or 
(ii)whether the puffers choose not to come because they sense a predator in the grey fox.

Choice E in my opinion is helpful in determining neither. It only says what can be inferred from the passage, because
what the passage says is:

(i) puffers spend the summers in the coastal areas and
(ii) their numbers has reduced in the coastal park

So it can be inferred from what is said in the passage alone that their numbers in the other coastal areas would have increased

Thus choice E doesn't provide any additional information. The other choices are wrong too.

nick28 · Answer

Hi,

Can someone please explain why B cannot be the answer.

As per B, if the grey fox is also eating Mulberry tree fruits then there would be only a few left for the birds to enjoy themselves and hence birds number is declining in that park.

So once we determine that this is not the reason for declining numbers of birds then we can safely evaluate the argument that the reduction in number of birds is more out of fear of fox.

SVaidyaraman · Answer

Hi nick28,

Good point. I will say my views on your point soon

nick28 · Answer

yes Mike, that does clear things out.

thanks for the explanation!

SVaidyaraman · Answer

Sorry I didn't see it was the seeds. B is indeed wrong. But my original argument stands. E is not a good choice either.

pavan2185 · Answer

what is the problem with D. is it not important to evaluate this issue ?

mikemcgarry · Answer

Dear pavan2185 , It's important to recognize --- on an " evaluate the argument " question, it's not a matter simply of finding something that be pertinent ---- the job is to find a deciding question. If I know the answer to such-and-such question, then this will mean the arguments stands or falls? Answers (A) - (D) all could be considered vaguely relevant --- that's precisely what makes them good distractors --- but even if we knew the precise answer to any of them, it wouldn't help us decide: is the argument correct? The conclusion of the argument we are trying to evaluate is: " Clearly, the Puffers .... are choosing to spend their summers elsewhere. " In other words, there aren't fewer Puffers because they died or were killed by the fox; rather, they are alive & healthy somewhere else. That's the argument. Now, suppose someone with the information came along and gave us a definitive answer to (D) ---- either, " Yes, the range of the grey fox within the park extends all the way to the coast " or " No, the range of the grey fox within the park doesn't get anywhere near the coast ." Suppose we had one of these two answers, completely verified without a shadow of a doubt. OK, we know the range of the grey fox. Now what? What does this tell us about what happened to the Puffers? Suppose the former is the answer: suppose the grey fox occupy every square inch of the park all the way out to the coast. Even then, what does this imply about the Puffers? Have they all been eaten by the fox, or have they all gone somewhere else? Notice, that even if we have definitive information about the range of the grey fox, a definitive answer to (D) , we can't answer this core question. There's a huge difference between a vaguely relevant question, again as (A) - (D) all are, and a deciding question, which is precisely what (E) is. Does this make sense? Mike :-)

mikemcgarry · Answer

With all due respect, the way you are discussing this question format does not resonate with my understanding of how they are presented in the OG. To the best of my knowledge, of all the "evaluate the argument" CR questions in the OG, not a single one involves questioning the premise. They all resolve on identifying some other crucial consideration that could be critical for the success of the argument. If you are aware of any specific "evaluate the argument" CR question in the OG, the answer to which actually questions the premise itself, I would be most curious to see that question. Of course, by definition, in all of the questions, the OA has significant implications for the conclusion. For example here, the conclusion is, simplistically: " The Puffers are not here, so they must be somewhere else " and (E) investigates whether they are, in fact, somewhere else. Does all this make sense? Mike :-)

sgangs · Answer

@Mike......
I have a doubt regarding the OE.

Let me ask the question...

Quote:

Whether other coastal areas in the state have seen an increase in the number of blue-tipped Puffers over the last decade

Now there are 2 situations:
Case - 1
Thomson's Blueberry trees are present in the other coastal areas of the state ( gimme an SC view on it, is it grammatically wrong??).
So, once these birds stop coming to the Coastal Park they can be assumed to go to the other coastal areas.

So a yes-no answers the situation differently & helps us.

However, look at Case-2

Thomson's Blueberry trees are not present in the other coastal areas of the state.

Now, the yes-no answer doesn't really matter. Does it??? The birds can go to any state - Johnson, Robinson, Wilson

etc to chew on Thomson.

Hence and increase or not, it doesn't bother us!!

So.... hw is it tht OA is E ????

etc to chew on Thomson. Hence and increase or not, it doesn't bother us!! So.... hw is it tht OA is E ????

mikemcgarry · Answer

Dear sgangs I'm happy to respond. :-)

We are told in the prompt: " The Puffers enjoy the seeds of Thomson’s Mulberry trees; because these trees are plenty in the state’s Coastal Park, traditionally many blue-tipped puffers would be found in the park during summer months ." Does this mean that the Puffers eat only the seeds of Thomson’s Mulberry trees? No. I don't know a whole lot about birds, but my sense is that most birds eat more than one kind of seed, much as fruit-eating animals tend to eat more than one kind of fruit and much as meat-eating animals tend to eat more than one kind of meat. There is certainly nothing in the prompt that suggests that the Puffers' diet is limited to only one kind of seed. Perhaps they " enjoy " that seed more than any other for some reason, but their survival is not dependent on it. That would be too much of an assumption to make. If the Puffers have gone to other parks alone the coast, then 1) maybe, as you say, Thomson's Blueberry trees are present in the other coastal areas of the state (perfectly correct from a SC view), and the Puffers eat those seeds in those places or 2) maybe they are few or no Thomson's Blueberry trees, and the Puffers eat other kinds of seeds there The nature of the diet is not so much of an issue. Yes, the birds seem particularly to like one kind of seed, but if the birds are in a region to which they climatically adapted, then most likely they will find enough of some kind of seeds to eat. Birds don't each much --- do you know the phrase " to eat like a bird "? As long as birds are in some kind of natural setting, starving to death typically isn't a problem for our feathered friends. The big issue is: have they Puffers gone somewhere else, or have they all be eaten and wiped out by the grey fox? If we see them in other parks, then we know they are alive & well elsewhere. If we don't see them in any other park along that coast, well then that at least begins to suggest the conclusion is false, and in fact, the Puffers are no longer here because they were lunch for the fox. Choice (E) address this crucial issue: are the Puffers found elsewhere or not? Does all this make sense? Mike :-)

sgangs · Answer

Mike, tell me 1 thing.. If we dont see their (puffers) increase in the coast of the said state, how can we assume that the fox are having awesome summer dinner??
It can be that the birds have stopped coming to the state & are thriving in the coast of the adjoining state???

I was wrong about the thomson & seed part, but migratory birds travel a long way so they can altogether shift states. Had the option said the "whether the coastal areas across the gobe with similar conditions have seen an increase in puffers' population?" it would have been right.

Please correct me

mikemcgarry · Answer

Dear sgangs , It's true, if we look in other coastal regions and see an increase in Puffers, we know exactly what happened: that's where they went. If we look in other coastal regions and don't see the Puffers, we are on much less certain ground as far as what exactly happened to them --- fox dinner? in other state or country? The conclusion is: Clearly, the Puffers, sensing a potential predator in the fox, are choosing to spend their summers elsewhere . Getting a " yes " answer to the issue posed in (E) , see the Puffers in another nearby park, would completely resolve the question posed by the conclusion. Getting a " no " answer, not finding the Puffers, would still leave us in the dark. Many times, the " evaluate the argument " questions on the GMAT CR are exactly like this --- the correct answer is something in which one answer (" yes " or " no ") would completely illuminate the entire issue, but the opposite answer would still leave us in the dark. That's simply the nature of the question type. You seem to want an answer which will give us complete certainty regardless of whether we answer " yes " or " no " to it. That's a higher bar than the GMAT sets. Don't fall into the trap of looking for answers more perfect than what the GMAT will provide for you. It's true, we know zilch about the size of the state, the migratory range of the birds, etc. etc. All that may or may not be relevant. BUT, if we look at the next park up the coast, and it's full of Puffers, all our questions are answered, and these other issues wouldn't matter. Does all this make sense? Mike :-)

sgangs · Answer

Aweesumm!!!!!! Had you and the whole team of GmatClub not been here...then God knows what wud've happened!!!!! Kuddooosss to u all (Wht'll u all do with kudos??? Share the ones u all get with us

)!!!! I was looking for extremes in the answer (remember thts wht all books, including CR Bible writes. Thanks for the alternative

jlgdr · Answer

Agree with SravnaPrep on this one. All answer choices are wrong.

Thread closed

mikemcgarry · Answer

Dear  jlgdr ,
My friend, I would say this is a bit dismissive for a question you don't fully understand. 
Mike

ssriva2 · Answer

The blue-tipped Puffer is a migratory bird that is found along the coast of this state in summer months. The Puffers enjoy the seeds of Thomson’s Mulberry trees; because these trees are plenty in the state’s Coastal Park, traditionally many blue-tipped puffers would be found in the park during summer months. Ten years ago, the grey fox was re-introduced into the park, and their number have been thriving. Over that time, we have seen many fewer Puffers in the park during the summer months. Clearly, the Puffers, sensing a potential predator in the fox, are choosing to spend their summers elsewhere.

Which of the following would be the most important to determine in order to evaluate the argument?

(A) What other birds and small mammals the grey fox typically hunts besides the blue-tipped Puffers.
(B) Whether the grey fox eats the fruit of the Thomson’s Mulberry trees.
(C) How the speed of a blue-tipped Puffer during take-off from the ground compares to the speed of a grey fox running
(D) Whether the range of the grey fox within the park extends all the way to the coast.
(E) Whether other coastal areas in the state have seen an increase in the number of blue-tipped Puffers over the last decade.

For a general discussion of Evaluation the Conclusion GMAT CR questions, as well as a complete explanation of this question, see:
https://magoosh.com/gmat/2013/gmat-criti ... onclusion/

Mike :-)

April, 2015:
UPDATE: this question had some problems and has been revised. Please see the revised version here:
https://gmat.magoosh.com/questions/3794

Mike :-)

Show Answer

Official Answer

E

mikemcgarry · Answer

Dear ssriva2 , My friend, there is no way you could have known this, but our internal stats at Magoosh revealed some subtle problems with this question, so we revised it. A revised version appears here: https://gmat.magoosh.com/questions/3794 Forget about the old version. Do this new version, and tell me if you still have questions. Mike :-)

The blue-tipped Puffer is a migratory bird that is found

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The blue-tipped Puffer is a migratory bird that is found

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