We see that the bird , by spinning, create upwelling currents, and the plankton it eats is usually concentrated below the surface. It is logical to suspect that the birds spins for this reason, but it may be that the bird spins for other reasons. If E were false, i.e. if the bird spun even when it has plankton within easy reach, we should suspect that the bird spins for some other reason. If the bird has all of the food it wants, why should it waste energy spinning?
Valerie wears high-heeled shoes when she goes to discoteques, even though she is more comfortable in running shoes. Men thus think that she is really taller than she is, and men are known to be attracted to tall women. Is it clear that Valerie wears high-heeled shoes to attract men? What if it's true that she wears high heels even when she visits her parents in a nursing home where the staff is entirely female?
Aquatic birds known as phalaropes
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kevincanspain
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kevincanspain
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When feeding, aquatic birds known as phalaropes often spin rapidly on the water's surface, pecking for food during each revolution. To execute these spins, phalaropes kick one leg harder than the other. This action creates upwelling currents. Because plankton on which phalaropes feed typically occurs in greater quantities well below the surface, it is hypothesized that by spinning phalaropes gain access to food that would otherwise be beyond their reach.
Which of the following, if true, most strongly supports the hypothesis?
A. Phalaropes rarely feed while on land.
B. A given phalarope spins exclusively either to the right or to the left.
C. Phalaropes sometimes spin when they are not feeding.
D. Different phalaropes spin at somewhat different rates.
E. Phalaropes do not usually spin when food is abundant at the surface.
Which of the following, if true, most strongly supports the hypothesis?
A. Phalaropes rarely feed while on land.
B. A given phalarope spins exclusively either to the right or to the left.
C. Phalaropes sometimes spin when they are not feeding.
D. Different phalaropes spin at somewhat different rates.
E. Phalaropes do not usually spin when food is abundant at the surface.
Kevin Armstrong
GMAT Instructor
Gmatclasses
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GMAT Instructor
Gmatclasses
Madrid
