A. Phalaropes rarely feed while on land.---out of scope
B. A given phalarope spins exclusively either to the right or to the left.---out of scope
C. Phalaropes sometimes spin when they are not feeding.---weakener
D. Different phalaropes spin at somewhat different rates.---out of scope
E. Phalaropes do not usually spin when food is abundant at the surface. ---we can check this answer by negation. If phalaropes DO usually spin when food is abundant at the surface. [i]This answers clearly breaks the conclusion. [/i]

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?

Pr.: Phalaropes spin rapidly on water’s surface, pecking for food during each revolution which occurs in greater quantities well below the surface.
Conc.: By spinning, Phalaropes gain access to food that would otherwise be beyond their reach.

A. Phalaropes rarely feed while on land - Doesn't affect argument. Even if they feed primarily on water's surface, it doesn't mean that they do it while spinning.
B. A given phalarope spins exclusively either to the right or to the left - No effect on conclusion how they spin.
C. Phalaropes sometimes spin when they are not feeding - mild weakener instead of strengthener.
D. Different phalaropes spin at somewhat different rates - Irrelevant.
E. Phalaropes do not usually spin when food is abundant at the surface - Correct. It supports hypothesis by stating that they do spin only when food is scarce and do not spin when it is abundant.

Kudos please.....
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options A,B and D are out of scope options
option C is actually weakening the argument
correct answer - E

Premise: When feeding, aquatic birds known as phalaropes often spin rapidly on the water’s surface, pecking for food during each revolution.
Premise: To execute these spins, phalaropes kick one leg harder than the other.
Premise: This action creates upwelling currents.
Conclusion: 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?
Question Type: Strength
Prephase: Kicking related to spinning related to food.

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. - As highlighted in the passage if food is readily available at shallow depths, the need for the birds to spin does not arise.

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