Mayor: Migrating shorebirds stop at our beach just to feed on horseshoe-crab eggs, a phenomenon that attracts tourists. To bring more tourists, the town council plans to undertake a beach reclamation project to double the area available to crabs for nesting.
Birdwatcher: Without a high density of crabs on a beach, migrating shorebirds will go hungry because shorebirds only eat eggs that a crab happens to uncover when it is digging its own nest.
Which of the following, if true, would provide the mayor with the strongest counter to the birdwatcher's objection?
A. Every year a certain percentage of crabs are caught by fishermen as bait for eel traps.
B. Horseshoe crabs are so prolific that given favorable circumstances their numbers increase rapidly.
C. On average, tourists who come to the town in order to watch birds spend more money there than tourists who come for other purposes.
D. The additional land made available by the reclamation project will give migrating shorebirds more space.
E. Some of the migrating shorebirds make only one stop during their migration form South America to Canada.
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Migrating shorebirds
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captainfriend
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This is a question that, upon first read, may seem vaguely illogical and abstruse. The key phrase is this: “shorebirds only eat eggs that a crab happens to uncover when it is digging its own nest,” which means that crabs dig their own nest, and thus accidentally uncover the eggs buried of nearby nests, and this is in fact what brings birds, which in turn brings tourists. This provides the link needed for the birdwatcher’s argument; there must be a dense population of crabs for this accidental uncovering to occur; therefore, increasing the space in which crabs can nest will decrease the density, and decrease the number of accidental uncoverings. This is at the heart of the birdwatcher's argument.
However, there is a key assumption in the birdwatcher's argument: increasing the space for crab nesting will ONLY result in a decrease in crab density IF there is not a proportionate increase in crabs. In other words, if there were double the space, AND DOUBLE THE CRABS, the crab density would remain stable. We'd get more accidental egg uncovering, more birds, and more tourists; the birdwatcher would be wrong in her conclusion, and the mayor right.
Answer choice B reflects this logic, explaining that horseshoe crabs are both “prolific” and that their number increases rapidly given favorable circumstances (such as a beach reclamation project to give them extra space).
The other answer choices are mismatches. Choice A is about decreases, not increases, in crab population (and goes by percentage, which means that this situation would not change even if the population did). Choice C is about money, and far out of scope; the argument is about bringing more tourists, not about bringing more tourist money. Choice D is irrelevant and redundant: crabs have more space, so do birds- so what? Choice E discusses an irrelevant fact that has no direct bearing on the situation; we already know that birds stop here to get eggs, so we can safely assume they will continue to do so.
Following the thread of causation (in this case- crab density :arrow: crabs uncovering eggs :arrow: more birds :arrow: more tourists) is key, here and on many CR questions.
Alex
Knewton Verbal Head
However, there is a key assumption in the birdwatcher's argument: increasing the space for crab nesting will ONLY result in a decrease in crab density IF there is not a proportionate increase in crabs. In other words, if there were double the space, AND DOUBLE THE CRABS, the crab density would remain stable. We'd get more accidental egg uncovering, more birds, and more tourists; the birdwatcher would be wrong in her conclusion, and the mayor right.
Answer choice B reflects this logic, explaining that horseshoe crabs are both “prolific” and that their number increases rapidly given favorable circumstances (such as a beach reclamation project to give them extra space).
The other answer choices are mismatches. Choice A is about decreases, not increases, in crab population (and goes by percentage, which means that this situation would not change even if the population did). Choice C is about money, and far out of scope; the argument is about bringing more tourists, not about bringing more tourist money. Choice D is irrelevant and redundant: crabs have more space, so do birds- so what? Choice E discusses an irrelevant fact that has no direct bearing on the situation; we already know that birds stop here to get eggs, so we can safely assume they will continue to do so.
Following the thread of causation (in this case- crab density :arrow: crabs uncovering eggs :arrow: more birds :arrow: more tourists) is key, here and on many CR questions.
Alex
Knewton Verbal Head
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gmatmachoman
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mehravikas
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helpme_2009
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IMO B
mayor- claims the phenomenon in which the shorebirds feed on horseshoe-crab eggs attracts tourists. so to inc this he wants to inc the availble area for inc number of crab . his reasoning is that it will help the shorebirds .
birdwatcher counter this by claiming that inc space will reduce denseity of crab and therefore shorebirds will go hungry.
task is to weak birdwatchers arument.
which is stated in B that the density will not decrease as more space will favor crabs to inc their number.hence density will not be reduced
mayor- claims the phenomenon in which the shorebirds feed on horseshoe-crab eggs attracts tourists. so to inc this he wants to inc the availble area for inc number of crab . his reasoning is that it will help the shorebirds .
birdwatcher counter this by claiming that inc space will reduce denseity of crab and therefore shorebirds will go hungry.
task is to weak birdwatchers arument.
which is stated in B that the density will not decrease as more space will favor crabs to inc their number.hence density will not be reduced
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turbo jet
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IMO: B
Agree with the explanation given by Knewton.
Ans B tells us that crab egg density will not be a problem as pointed by the birdwatcher and hence strengthens.
Cheers
TJ
Agree with the explanation given by Knewton.
Ans B tells us that crab egg density will not be a problem as pointed by the birdwatcher and hence strengthens.
Cheers
TJ
Life is Tom; I am Jerry 
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heshamelaziry
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WOW..Really impressive explanation. HOw long did you spend to understand the logic of the question ? Do you know if this is an upper level question because it is difficult to put ideas together ?captainfriend wrote:This is a question that, upon first read, may seem vaguely illogical and abstruse. The key phrase is this: �shorebirds only eat eggs that a crab happens to uncover when it is digging its own nest,� which means that crabs dig their own nest, and thus accidentally uncover the eggs buried of nearby nests, and this is in fact what brings birds, which in turn brings tourists. This provides the link needed for the birdwatcher�s argument; there must be a dense population of crabs for this accidental uncovering to occur; therefore, increasing the space in which crabs can nest will decrease the density, and decrease the number of accidental uncoverings. This is at the heart of the birdwatcher's argument.
However, there is a key assumption in the birdwatcher's argument: increasing the space for crab nesting will ONLY result in a decrease in crab density IF there is not a proportionate increase in crabs. In other words, if there were double the space, AND DOUBLE THE CRABS, the crab density would remain stable. We'd get more accidental egg uncovering, more birds, and more tourists; the birdwatcher would be wrong in her conclusion, and the mayor right.
Answer choice B reflects this logic, explaining that horseshoe crabs are both �prolific� and that their number increases rapidly given favorable circumstances (such as a beach reclamation project to give them extra space).
The other answer choices are mismatches. Choice A is about decreases, not increases, in crab population (and goes by percentage, which means that this situation would not change even if the population did). Choice C is about money, and far out of scope; the argument is about bringing more tourists, not about bringing more tourist money. Choice D is irrelevant and redundant: crabs have more space, so do birds- so what? Choice E discusses an irrelevant fact that has no direct bearing on the situation; we already know that birds stop here to get eggs, so we can safely assume they will continue to do so.
Following the thread of causation (in this case- crab density :arrow: crabs uncovering eggs :arrow: more birds :arrow: more tourists) is key, here and on many CR questions.
Alex
Knewton Verbal Head
-
gmatmachoman
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