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SVP
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During the day in Lake Constance,the zoo-plankton Dahyalina departs for the depths where food is scarce and the water cold. Dagaleata remains near the warm surface where food is abundant. Even though Dagaleata grows and reproduces much faster, its population is often outnumbered by Dahyalina.
Which of the following, if true, would help resolve the apparent paradox presented above?
(A) The number of species of zooplankton living at the bottom of the lake is twice that of species living at the surface.
(B) Predators of zooplankton, such as white-fish and perch,live and feed near the surface of the lake during the day.
(C) In order to make the most of scarce food resources, Dahyalina matures more slowly than Dagaleata.
(D) Dagaleata clusters under vegetation during the hottest part of the day to avoid the sun's rays.
(E) Dagaleata produces twice as many offspring per individual an any given period of time as does Dahyalina.
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Manager
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B?
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SVP
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do you know the answers?
why B?
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Manager
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Stolyar, I don't know the answers - I'm reading these for the first time!
My logic is the following:
Given the food and temperature conditions at the surface and in the depths, the population of Dahyalina would be more than Dagaleata only in two cases
(A) The number of species of zooplankton living at the bottom of the lake is twice that of species living at the surface
OR
(B) Predators of zooplankton, such as white-fish and perch,live and feed near the surface of the lake during the day
To me, the choice A seems unreal since the food is scarce in the depths. Therefore, I chose B
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SVP
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The predateors may eat both Ds. there is no word that white-fish prefers Dagaleata. I voted for D.
You see how stupid I am and why I managed to get 670 on the test!
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Manager
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Don't be too harsh on yourself !
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Manager
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stolyar wrote: During the day in Lake Constance,the zoo-plankton Dahyalina departs for the depths where food is scarce and the water cold. Dagaleata remains near the warm surface where food is abundant. Even though Dagaleata grows and reproduces much faster, its population is often outnumbered by Dahyalina.
Which of the following, if true, would help resolve the apparent paradox presented above?
(A) The number of species of zooplankton living at the bottom of the lake is twice that of species living at the surface.
(B) Predators of zooplankton, such as white-fish and perch,live and feed near the surface of the lake during the day.
(C) In order to make the most of scarce food resources, Dahyalina matures more slowly than Dagaleata.
(D) Dagaleata clusters under vegetation during the hottest part of the day to avoid the sun's rays.
(E) Dagaleata produces twice as many offspring per individual an any given period of time as does Dahyalina.
This may be a small point, but it appears important that the passage does not refer to Dagaleata as zoo-plankton. It does refer to Dahyalina as zoo-plankton. Therefore a predator of zoo-plankton would only be interested in eating Dahyalina, which they don't find because it has retreated to the bottom.
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SVP
Joined: 03 Feb 2003
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Dagaleata is NOT zoo-plankton
Dahyalina is zoo-plankton
Therefore, a predator of zoo-plankton would only be interested in eating Dahyalina, decimating it.
BUT, Dahyalina, nevertheless, PROSPERS as the passage says.
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GMAT Instructor
Joined: 07 Jul 2003
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Schools: Haas, MFE; Anderson, MBA; USC, MSEE
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Is this an ETS question? (They are usually carefully about ambiguity).
My reasoning would be:
1) Although Dagaleata is not identified as a Z-P, neither does the passage say that it is NOT one. Hence, within the context of the passage, I will infer that it is.
2) Dah-eata both grows and reproduces faster than Dag-lina. Hence, the only way that Dag-eata will have less than Dag-lina over time is that the Dah-eata are dying faster.
3) (B) provide a reasonable premise that supports the conclusion. IMO, none of the others do. A is irrelavent, we are concerned with only 2 species. C does not help resolve the paradox, since a longer growing period implies a later time to reproduce. D) is irrelevant -- the clustering does nothing to explain the paradox. E) makes the paradox harder to explain.
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AkamaiBrah
Former Senior Instructor, Manhattan GMAT and VeritasPrep
Vice President, Midtown NYC Investment Bank, Structured Finance IT
MFE, Haas School of Business, UC Berkeley, Class of 2005
MBA, Anderson School of Management, UCLA, Class of 1993
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I found it in one of Asian GMAT sites.
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Current Student
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Alternative cause discrepency CR. Got a little confused about the two types of plankton at the beginning..
(B)
:46
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VP
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Reproduction rate is high..but numbers are low..means mortality rate is high...B provides the answer..
_________________
The path is long, but self-surrender makes it short;
the way is difficult, but perfect trust makes it easy.
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