Some species of Arctic birds are threatened by recent sharp increases in the population of snow geese, which breed in the Arctic and are displacing birds of less vigorous species.Although snow geese are a popular quarry for hunters in the southern regions where they winter, the hunting season ends if and when hunting has reduced the population by five percent, according to official estimates.Clearly, dropping this restriction would allow the other species to recover.
Which of the following, if true, most seriously undermines the argument.
A.Hunting limits for snow geese were imposed many years ago in response to a sharp decline in the population of snow geese.
B.It has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date.
C.The number of snow geese taken by hunters each year has grown every year for several years.
D.As their population has increased, snow geese have recolonized wintering grounds that they had not used for several seasons.
E.In the snow goose’s winter habitats, the goose faces no significant natural predation.
知道答案还是不知怎么解释，请NN帮帮忙！作者: xuyuanwai 时间: 2013-5-20 06:33
很多年来 the restriction 都比the scheduled date 要提早结束，the
scheduled date 只的是：when hunting has reduced the population by five
