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ants of most species leave a trail of chemicals

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by thephoenix » Fri Apr 30, 2010 10:10 pm
On their way from their nest to a food source, ants of most species leave a trail of chemicals called pheromones. The ants use the scent of the pheromones to guide themselves between the food and their nest. All pheromones evaporate without a trace almost immediately when temperatures rise above 45 degrees Celsius (113 degree Fahrenheit), as is typical during afternoons in places such as the Sahara Desert.
The statements above, if true, most strongly support which one of the following?
(A) Most ants forage for food either only in the morning or only during the night.
(B) Most ants that do not use pheromones to mark the paths they take between their nest and food live in the Sahara Desert.
(C) If any ants live in the Sahara Desert and forage for food at no time but in the afternoon, those ants generally do not use pheromones to guide themselves between food and their nest.
(D) If any ants do not use pheromones to navigate between food and their nest, those ants use a different substance that does not evaporate in temperatures above 45 degrees Celsius.
(E) If any Saharan ants forage for food in the afternoon, those ants forage for food less efficiently when temperatures are above 45 degrees Celsius than they do when temperatures are lower.
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Source: — Critical Reasoning |

by beat_gmat_09 » Fri Apr 30, 2010 10:28 pm
thephoenix wrote:On their way from their nest to a food source, ants of most species leave a trail of chemicals called pheromones. The ants use the scent of the pheromones to guide themselves between the food and their nest. All pheromones evaporate without a trace almost immediately when temperatures rise above 45 degrees Celsius (113 degree Fahrenheit), as is typical during afternoons in places such as the Sahara Desert.
The statements above, if true, most strongly support which one of the following?
(A) Most ants forage for food either only in the morning or only during the night.
(B) Most ants that do not use pheromones to mark the paths they take between their nest and food live in the Sahara Desert.
(C) If any ants live in the Sahara Desert and forage for food at no time but in the afternoon, those ants generally do not use pheromones to guide themselves between food and their nest.
(D) If any ants do not use pheromones to navigate between food and their nest, those ants use a different substance that does not evaporate in temperatures above 45 degrees Celsius.
(E) If any Saharan ants forage for food in the afternoon, those ants forage for food less efficiently when temperatures are above 45 degrees Celsius than they do when temperatures are lower.
IMO B.
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by thephoenix » Fri Apr 30, 2010 10:34 pm
beat_gmat_09 wrote:
thephoenix wrote:On their way from their nest to a food source, ants of most species leave a trail of chemicals called pheromones. The ants use the scent of the pheromones to guide themselves between the food and their nest. All pheromones evaporate without a trace almost immediately when temperatures rise above 45 degrees Celsius (113 degree Fahrenheit), as is typical during afternoons in places such as the Sahara Desert.
The statements above, if true, most strongly support which one of the following?
(A) Most ants forage for food either only in the morning or only during the night.
(B) Most ants that do not use pheromones to mark the paths they take between their nest and food live in the Sahara Desert.
(C) If any ants live in the Sahara Desert and forage for food at no time but in the afternoon, those ants generally do not use pheromones to guide themselves between food and their nest.
(D) If any ants do not use pheromones to navigate between food and their nest, those ants use a different substance that does not evaporate in temperatures above 45 degrees Celsius.
(E) If any Saharan ants forage for food in the afternoon, those ants forage for food less efficiently when temperatures are above 45 degrees Celsius than they do when temperatures are lower.
IMO B.
IMO
B is commenting about the group other than discussed in the stimulus , and therefore i eliminated it considering it Scope shift type of ans
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by paddle_sweep » Fri Apr 30, 2010 10:39 pm
IMO it's [spoiler]'E'[/spoiler].


Pls post OA.
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by kaushals » Sat May 01, 2010 2:45 pm
IMO [E][/spoiler]
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by kaushals » Sat May 01, 2010 2:46 pm
IMO E
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by ansumania » Sat May 01, 2010 7:54 pm
IMO C; Pl. post OA
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by liferocks » Sat May 01, 2010 9:23 pm
I will go with option C
was confused between C and E but the premise does not comment anything about the usage of pheromone and effectiveness of forage.
hence will go with C
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by Testluv » Sat May 01, 2010 9:36 pm
As liferocks points out, how efficiently they forage for food doesn't necessarily have anything to do with how well they go back and forth between the nest and food sources. Thus, choice E is outside the scope, and could easily be false.

Choice C must be true, and is correct. We know that ALL pheremones evaporate above a certain temperature, and that this threshold temperature is "typical" in afternoons in the Saharan desert. Thus, if there are some ants in the Sahara that forage for food only in the afernoon, they must be using something other than pheremones to guide themselves between food and nest.
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This:
IMO
B is commenting about the group other than discussed in the stimulus , and therefore i eliminated it considering it Scope shift type of ans
is great reasoning.
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