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举一反三
【单选题】Spring is usually prime food time for some 1,200 polar bears along Canada’’s Hudson Bay. Each year they plunder the bay’’s ice floes, smash open the snow caves of seals, and stuff themselves on seal p...
A.
The absorption of carbon dioxide by natural factors.
B.
Human effort to reduce carbon dioxide emissions.
C.
Drastically reduced emissions of greenhouse gases.
D.
A 10% decrease in the average weight of polar bears.