单选题

Which of the following, if true, most helps explain the difference in the rates of decline between 1980 and 1990 in population of puffins and arctic terns, two kinds of seabirds for which sand eels serve as a primary source of food?

A、 Puffinsswitched in part from their preferred food ofsand eelsto rockfish and other fish, but arctic terns did not
B、 The marked decline in the populations of puffins and arctic terns that occurred on Alair Island did not occur on other similar islands nearby, where there are substantial populations of both species
C、 The decline in sand eels was due to changes in environmental conditions that affected the reproduction of eels rather than to overfishing by people.
D、 The main diet of puffin and arctic tern chicks on Alair Island in 1980 consisted of young sand eels.
E、 Unusualsevere weather that disrupted the breeding cycle of the sand eels of Alair Island in 1989 also damaged the nests of puffins but not those of arctic terns.

【正确答案】 A

【答案解析】