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gmatnmein2010 wrote:Guillemots are birds of Arctic regions. They feed on fish that gather beneath thin sheets of floating ice, and they nest on nearby land. Guillemots need 80 consecutive snow-free days in a year to raise their chicks, so until average temperatures in the Arctic began to rise recently, the guillemots' range was limited to the southernmost Arctic coast. Therefore, if the warming continues, the guillemots' range will probably be enlarged by being extended northward along the coast.

Which of the following, if true, most seriously weakens the argument?

Conclusion gullimots range will enlarge by being extended northward along the coast

(A) Even if the warming trend continues, there will still be years in which guillemot chicks are killed by an unusually
early snow.
Incorrect : This does nothing to undermine the argument.

(B) If the Arctic warming continues, guillemots' current predators are likely to succeed in extending their own range
farther north.
Incorrect : There is slight scope shift from gulliemots range to gulliemots predators. Eliminated.

(C) Guillemots nest in coastal areas, where temperatures are generally higher than in inland areas.
Incorrect : Issue is not about guillemots nesting... its is about extending guillemots range.

(D) If the Arctic warming continues, much of the thin ice in the southern Arctic will disappear.
Correct : If the thin ice disappears, the guillemots source of food (fish that gather beneath thin sheets of floating ice) will not be available which in turn will threaten their survival. If the gulliemots dont survive the argument about their range enlargement is weakened.

(E) The fish that guillemots eat are currently preyed on by a wider variety of predators in the southernmost Arctic
regions than they are farther north.
Incorrect : This does not undermine the argument in any way.