Q11: 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.
答案选b不知道为什么正确,请高人给分析下下! Q23: Because visual inspection cannot reliably distinguish certain skin discolorations from skin cancers, dermatologists at clinics have needed to perform tests of skin tissue taken from patients. At Westville
Hospital, dermatological diagnostic costs were reduced by the purchase of a new imaging machine that diagnoses skin cancer in such cases as reliably as the tissue tests do. Consequently, even though the machine is expensive, a dermatological clinic in Westville is considering buying one to reduce diagnostic costs.
Which of the following would it be most useful for the clinic to establish in order to make its decision?
- Whether the visits of patients who require diagnosis of skin discolorations tend to be shorter in duration at the clinic than at the hospital
- Whether the principles on which the machine operates have been known to science for a long time
- Whether the machine at the clinic would get significantly less heavy use than the machine at the hospital does
- Whether in certain cases of skin discoloration, visual inspection is sufficient to make a diagnosis of skin cancer
- Whether hospitals in other parts of the country have purchased such imaging machines
不明白为什么是c选项
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