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08 Sep 2021, 09:19
Kudos
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B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
95%
(hard)
Question Stats:
41% (02:05) correct
59%
(02:12)
wrong
based on 219
sessions
History
Date
Time
Result
Not Attempted Yet
Kiki birds breed more effectively in some temperatures than in others. During the period from 1991 to 1995, the kiki bird population in a certain region increased, despite a moratorium, or official ban, on the hunting of the kiki bird's chief predator. During the period from 1996 to 2000, the kiki bird population in the same region declined, despite ideal breeding temperatures during that period.
Which of the following, if true, best explains why the kiki bird population increased during the period from 1991 to 1995, then declined during the period from 1996 to 2000?
(A) During the period from 1991 to 1995, temperatures in the region were ideally suited for kiki bird breeding.
(B) The moratorium on the hunting of the kiki bird's chief predator was rigorously enforced only after 1995.
(C) Ideal breeding temperatures for the kiki bird's chief predator differ from those for the kiki bird.
(D) The kiki bird is only one of many animal species that is potential prey for the bird's chief predator.
(E) During the period from 1996 to 2000, the population of the kiki bird's chief predator increased throughout the region.
Which of the following, if true, best explains why the kiki bird population increased during the period from 1991 to 1995, then declined during the period from 1996 to 2000?
(A) During the period from 1991 to 1995, temperatures in the region were ideally suited for kiki bird breeding.
(B) The moratorium on the hunting of the kiki bird's chief predator was rigorously enforced only after 1995.
(C) Ideal breeding temperatures for the kiki bird's chief predator differ from those for the kiki bird.
(D) The kiki bird is only one of many animal species that is potential prey for the bird's chief predator.
(E) During the period from 1996 to 2000, the population of the kiki bird's chief predator increased throughout the region.
08 Sep 2021, 10:48
Kudos
Bookmarks
First I read the question:
So this is an 'explain' CR question. These questions present something that is--to the author--unexpected or surprising. It will be up to us to explain how that thing happened.
In many ways, I think of these as 'weaken' the argument questions. The author WOULD HAVE concluded the opposite of what happened. I need to figure out what the author WOULD HAVE reasoned to make that conclusion, and show why it's wrong.
Then I read the passage:
So there's something strange going on here, and I'm thinking it's a typo. Why would an 'official ban' on 'hunting the bird's chief predator' not lead to the population to increase? The word 'despite' seems illogical in this instance... So I'm assuming it's a typo and that it's supposed to be 'due to.'
{NOTE AFTER THE FACT, in case you're confused right now: this was BAD THINKING! Keep reading}
With that correction, I do a little critical reasoning. The bird population increased when there was this moratorium on hunting the bird's predators. Then, despite having an ideal temperature for the birds, the population of birds declined.
Well, my immediate thought is 'did the moratorium end?' If the population surged during a moratorium, might it then decline if the moratorium ended and people started killing the predators again? That seems very likely.
Other than that, I'm thinking about some general thing that could lower the birds' population even with a good temperature for them.
I go to answers with this 'goal' in mind.
This helps add explanation to why their population surged at first, not why it then dropped. Eliminate.
This only makes the surprise more extreme. If the moratorium on hunting the predator was not enforced *during* the surge, but was enforced *during the decline?* That would mean the predators were killed more as the bird population dropped. That doesn't explain why the population dropped, it makes it even weirder that the population dropped.
This has me curious. It's one of those answers that 'surprises' me, because I hadn't even considered breeding temperature for the predator... I think it's wrong, but I don't want to waste time on it at the moment, so I'll keep it and move on.
This doesn't seem relevant. Nowhere is the reasoning dependent on the other prey (or lack of prey) for the predator.
Well this seems to be exactly my goal? If the population of the predator surged in the years of the kiki birds' decline, that makes sense, even when the temperature was good for the bird. I choose E.
...And the answer is B.
Okay, so either this question is poorly formed, or my reasoning is wrong. I'm going to first presume my reasoning is wrong and try to figure out why.
There are three reasons we miss CR questions: (See: https://www.youtube.com/watch?v=Xem2vqSyenE)
The first is MISREADING/MISINTERPRETING THE QUESTION/PASSAGE.
So I read those to make sure I haven't misunderstood something.
So in the question, I think I read it right. I'm trying to explain why the bird's population went up for 5 years, and then dropped for 5 years. (I am realizing now, though, that my answer/reasoning doesn't much deal with the *first* part of this question, and more addresses why the population dropped in the last 5 years... Keep that in mind because it can be important!)
I now reread the passage to make sure I interpreted it correctly.
Yep, okay. I made a mistake. It's a mistake I thought was the passage's mistake! (Lesson there...)
I really should have written down a causal chain here to understand what that 'moratorium' really meant:
Moratorium on hunting predators ----->No more killing predators (according to rules, anyway) ------->Predator population probably increases ------->More predators to eat birds -------->You'd expect bird population to decline.
I misinterpreted what the moratorium would entail. There are few reasons I think I might have done this:
1). A moratorium on hunting would cause a population to increase! ... Just not the population of the *birds*. Must be specific about categories and cause effect!
2). There's a trickly list of 'negations' going on. A 'BAN' on hunting predators would (reasonably) cause MORE predators, and MORE predators would (reasonably) cause LESS prey. So, we're NOT KILLING the animals that DO KILL the birds.
Somehow this feels like dealing with multiplying a string of negatives and positives together and making sure we're clear which negatives cancel and which don't... I was not careful about this. Again, WRITING DOWN is a good idea.
I also should have realized it's more likely I'm wrong than the question.
(ODDLY ENOUGH: I wrote this very relevant piece very recently: https://gmatclub.com/forum/one-of-the-h ... 67905.html
I was so certain of my incorrect interpretation, I didn't even check myself. OOPS. Note we're all prone to make these errors sometimes, even teachers who teach about them. I was a little more arrogant here, because I have found typos on GMAT club questions that aren't official questions, but it's always, always worth remembering your interpretation has a good chance of being wrong so check it carefully, don't let arrogance blind you).
So, now I see why B is correct. If the ban wasn't really enforced in the first time period, the predators were still hunted, and killed, leaving fewer to eat the birds. So the bird population went up. Then the ban was enforced, so the predators weren't hunted as much, so there were more of them around to eat the birds.
Now why is E wrong, because it seems kind of right??? Because it only explains why the population might decline in the back half. It doesn't explain why the bird population went up in the first half (even when the moratorium on hunting the predators existed, making one think the predator population might be going down).
Okay, so, what are the takeaways?
1). When dealing with a causal chain, WRITE DOWN THE CHAIN. Put it in front of you so you can SEE THE THING.
2). Check yourself, check yourself, check yourself. As I wrote in that article (that I apparently ignored outright here), the GMAT is seeing how well/often you analyze your own interpretations and find mistakes. Your brain will convince you it is correct (as mine did here). I failed to notice my mind 'beartrap' on a misinterpretation of cause/effect.
It's especially important to do this when something seems wrong. When something doesn't seem to make sense, either the problem is poorly written (...virtually no official GMAT question is) or your interpretation is wrong.
3). When dealing with multiple CATEGORIES, try to keep thoughts SPECIFIC TO WHICH CATEGORY. Avoid VAGUENESS. "The population decline" is vague. Which population? That of the preys? Or that of the predators? The two blended in my mind here when I wasn't specific about which (takeaway 1 would have really helped avoid this).
4). When a question asks to explain TWO THINGS, don't explain JUST ONE. That will not be sufficient in the GMAT's eyes.
Now, a lesson for ya'll: Notice how thoroughly I analyzed this. I put my process under the microscope here--as one has to for CR and RC (see again, that video on how to review RC and CR). I didn't have an explanation to read to figure out how I missed it, and I still figured it out. Even if you DO have an explanation, DO NOT USE IT TOO SOON. Do as much thinking yourself as you can. Find specific, concrete takeaways. Notice my takeaways also have a 'when' component to them. "WHEN there is a causal chain, write it down." "WHEN a question asks to explain two things..." "WHEN something doesn't seem to make sense..."
These give me specific contexts to notice in the problem or in myself, and the appropriate reaction to them.
Quote:
So this is an 'explain' CR question. These questions present something that is--to the author--unexpected or surprising. It will be up to us to explain how that thing happened.
In many ways, I think of these as 'weaken' the argument questions. The author WOULD HAVE concluded the opposite of what happened. I need to figure out what the author WOULD HAVE reasoned to make that conclusion, and show why it's wrong.
Then I read the passage:
Quote:
So there's something strange going on here, and I'm thinking it's a typo. Why would an 'official ban' on 'hunting the bird's chief predator' not lead to the population to increase? The word 'despite' seems illogical in this instance... So I'm assuming it's a typo and that it's supposed to be 'due to.'
{NOTE AFTER THE FACT, in case you're confused right now: this was BAD THINKING! Keep reading}
With that correction, I do a little critical reasoning. The bird population increased when there was this moratorium on hunting the bird's predators. Then, despite having an ideal temperature for the birds, the population of birds declined.
Well, my immediate thought is 'did the moratorium end?' If the population surged during a moratorium, might it then decline if the moratorium ended and people started killing the predators again? That seems very likely.
Other than that, I'm thinking about some general thing that could lower the birds' population even with a good temperature for them.
I go to answers with this 'goal' in mind.
Quote:
This helps add explanation to why their population surged at first, not why it then dropped. Eliminate.
Quote:
This only makes the surprise more extreme. If the moratorium on hunting the predator was not enforced *during* the surge, but was enforced *during the decline?* That would mean the predators were killed more as the bird population dropped. That doesn't explain why the population dropped, it makes it even weirder that the population dropped.
Quote:
This has me curious. It's one of those answers that 'surprises' me, because I hadn't even considered breeding temperature for the predator... I think it's wrong, but I don't want to waste time on it at the moment, so I'll keep it and move on.
Quote:
This doesn't seem relevant. Nowhere is the reasoning dependent on the other prey (or lack of prey) for the predator.
Quote:
Well this seems to be exactly my goal? If the population of the predator surged in the years of the kiki birds' decline, that makes sense, even when the temperature was good for the bird. I choose E.
...And the answer is B.
Okay, so either this question is poorly formed, or my reasoning is wrong. I'm going to first presume my reasoning is wrong and try to figure out why.
There are three reasons we miss CR questions: (See: https://www.youtube.com/watch?v=Xem2vqSyenE)
The first is MISREADING/MISINTERPRETING THE QUESTION/PASSAGE.
So I read those to make sure I haven't misunderstood something.
So in the question, I think I read it right. I'm trying to explain why the bird's population went up for 5 years, and then dropped for 5 years. (I am realizing now, though, that my answer/reasoning doesn't much deal with the *first* part of this question, and more addresses why the population dropped in the last 5 years... Keep that in mind because it can be important!)
I now reread the passage to make sure I interpreted it correctly.
Yep, okay. I made a mistake. It's a mistake I thought was the passage's mistake! (Lesson there...)
I really should have written down a causal chain here to understand what that 'moratorium' really meant:
Moratorium on hunting predators ----->No more killing predators (according to rules, anyway) ------->Predator population probably increases ------->More predators to eat birds -------->You'd expect bird population to decline.
I misinterpreted what the moratorium would entail. There are few reasons I think I might have done this:
1). A moratorium on hunting would cause a population to increase! ... Just not the population of the *birds*. Must be specific about categories and cause effect!
2). There's a trickly list of 'negations' going on. A 'BAN' on hunting predators would (reasonably) cause MORE predators, and MORE predators would (reasonably) cause LESS prey. So, we're NOT KILLING the animals that DO KILL the birds.
Somehow this feels like dealing with multiplying a string of negatives and positives together and making sure we're clear which negatives cancel and which don't... I was not careful about this. Again, WRITING DOWN is a good idea.
I also should have realized it's more likely I'm wrong than the question.
(ODDLY ENOUGH: I wrote this very relevant piece very recently: https://gmatclub.com/forum/one-of-the-h ... 67905.html
I was so certain of my incorrect interpretation, I didn't even check myself. OOPS. Note we're all prone to make these errors sometimes, even teachers who teach about them. I was a little more arrogant here, because I have found typos on GMAT club questions that aren't official questions, but it's always, always worth remembering your interpretation has a good chance of being wrong so check it carefully, don't let arrogance blind you).
So, now I see why B is correct. If the ban wasn't really enforced in the first time period, the predators were still hunted, and killed, leaving fewer to eat the birds. So the bird population went up. Then the ban was enforced, so the predators weren't hunted as much, so there were more of them around to eat the birds.
Now why is E wrong, because it seems kind of right??? Because it only explains why the population might decline in the back half. It doesn't explain why the bird population went up in the first half (even when the moratorium on hunting the predators existed, making one think the predator population might be going down).
Okay, so, what are the takeaways?
1). When dealing with a causal chain, WRITE DOWN THE CHAIN. Put it in front of you so you can SEE THE THING.
2). Check yourself, check yourself, check yourself. As I wrote in that article (that I apparently ignored outright here), the GMAT is seeing how well/often you analyze your own interpretations and find mistakes. Your brain will convince you it is correct (as mine did here). I failed to notice my mind 'beartrap' on a misinterpretation of cause/effect.
It's especially important to do this when something seems wrong. When something doesn't seem to make sense, either the problem is poorly written (...virtually no official GMAT question is) or your interpretation is wrong.
3). When dealing with multiple CATEGORIES, try to keep thoughts SPECIFIC TO WHICH CATEGORY. Avoid VAGUENESS. "The population decline" is vague. Which population? That of the preys? Or that of the predators? The two blended in my mind here when I wasn't specific about which (takeaway 1 would have really helped avoid this).
4). When a question asks to explain TWO THINGS, don't explain JUST ONE. That will not be sufficient in the GMAT's eyes.
Now, a lesson for ya'll: Notice how thoroughly I analyzed this. I put my process under the microscope here--as one has to for CR and RC (see again, that video on how to review RC and CR). I didn't have an explanation to read to figure out how I missed it, and I still figured it out. Even if you DO have an explanation, DO NOT USE IT TOO SOON. Do as much thinking yourself as you can. Find specific, concrete takeaways. Notice my takeaways also have a 'when' component to them. "WHEN there is a causal chain, write it down." "WHEN a question asks to explain two things..." "WHEN something doesn't seem to make sense..."
These give me specific contexts to notice in the problem or in myself, and the appropriate reaction to them.
General Discussion
15 Sep 2021, 04:30
Kudos
Bookmarks
LamboWalker
Official Explanation:
The correct answer is B. The passage presents a double-paradox: How could the bird's population increase in the face of an ostensible threat to its survival, then decrease when breeding conditions were ideal? A comprehensive explanation would need to account for both the increase and subsequent decrease in population. One explanation is that some other condition likely to have an impact on the kiki bird population changed from one time period to the other. (B) provides such a condition - a specific scenario that supports this explanation. Without enforcement of the moratorium, a greater number of the kiki bird's predators might be killed. which would tend to stabilize and perhaps even result in an increase in the kiki bird population. Conversely, enforcing the moratorium would tend to increase the predator's population, thereby possibly decreasing the bird's population.
Choice (A) explains why the kiki bird population increased from 1991 to 1995, but not why the kiki bird population declined from 1996 to 2000.
Choice (C) actually makes the paradox more inexplicable by providing an additional reason why the kiki bird population should have increased during the period from 1996 to 2000.
Choice (D) is completely irrelevant to the paradox - it serves neither to explain nor reinforce it.
Choice (E) explains why the kiki bird population decreased from 1996 to 2000, but not why the kiki bird population decreased from 1991 to 1995.
