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?
Hunting limits for snow geese were imposed many years ago in response to a sharp decline in the population of snow geese.
It has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date.
The number of snow geese taken by hunters each year has grown every year for several years.
As their population has increased, snow geese have recolonized wintering grounds that they had not used for several seasons.
In the snow goose's winter habitats, the goose faces no significant natural predation.
问削弱?也就是说如果废除了限制,不限制雪雁的捕猎,其他鸟儿的数量也不会recover?B项,雪雁已经有许多年没有提前禁止了,这说明雪雁的数量非常多,就算是打猎不限制,也hunt不了5%以上的雪雁,这几乎对雪雁的数量没有任何影响.。C项说的是每年雪雁的数量都有增加,但是这不能够彻底削弱,尽管增加,但是如果增加的不多,打猎不限制的情况下,数量会急剧下降,最终还是会减少许多。
B是说,距离上一次因为限制而导致捕猎季节提前结束 已经过去很多年了。而最近几年捕猎量一直没有达到5%的上限,所以即使放宽了5%的限制,也不能增加捕到雪雁的数量。
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近年即使猎到狩猎季结束,也捕不到5%。
所以,即使放开比例限制,也不能达到大幅减少鹅数的目的。