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?

• APhalaropes rarely feed while on land.  
• BA given phalarope spins exclusively either to the right or to the left.  
• CPhalaropes sometimes spin when they are not feeding.  
• DDifferent phalaropes spin at somewhat different rates.  
• EPhalaropes do not usually spin when food is abundant at the surface.