请教prep 两题。。。

gmatziyu

74.        (29534-!-item-!-188;#058&004138)

Ina certain wildlife park, park rangers are able to track the movements of manyrhinoceroses because those animals wear radio collars.  When, as often happens, a collar slips off,it is put back on.  utting a collar on arhinoceros involves immobilizing the animal by shooting it with a tranquilizerdart.  Female rhinoceroses that have beenfrequently recollared have significantly lower fertility rates than uncollaredfemales.  robably, therefore, somesubstance in the tranquilizer inhibits fertility.
Inevaluating the argument, it would be most useful to determine which of thefollowing?
A.Whether there are more collared female rhinoceroses than uncollared femalerhinoceroses in the park
B.How the tranquilizer that is used for immobilizing rhinoceroses differs, if atall, from tranquilizers used in working with other large mammals
C.How often park rangers need to use tranquilizer darts to immobilizerhinoceroses for reasons other than attaching radio collars
D.Whether male rhinoceroses in the wildlife park lose their collars any moreoften than the park’s female rhinoceroses do
E.Whether radio collars are the only practical means that park rangers have fortracking the movements of rhinoceroses in the park
请问这题为什么选C呢？
75.        (33198-!-item-!-188;#058&007254)

Inthe year following an eight-cent increase in the federal tax on a pack ofcigarettes, sales of cigarettes fell ten percent.  In contrast, in the year prior to the taxincrease, sales had fallen one percent. The volume of cigarette sales is therefore strongly related to theafter-tax price of a pack of cigarettes.
Whichof the following, if true, would most strengthen the argument above?
A.During the second year after the tax increase, cigarette sales increased by asignificant amount.
B.The information available to consumers on the health risks of smoking remainedlargely unchanged in the period before and after the tax increase.
C.Most consumers were unaware that the tax on cigarettes was going to increase.
D.During the year following the cigarette tax increase, many consumers had lessincome, in inflation-adjusted dollars, than they had had in the previous year.
E.During the year after the tax increase, there was a greater variety ofcigarettes on the market than there had been during the previous year.
请问这题为什么d不对呢？
谢谢

切尔西

开始也没有反应过来的，谢谢楼上的解释

cynthia1226

我的意思是，如果镇定剂不只用于attaching collar, 那就不能从collared的犀牛生育率低这个现象来推出是镇定剂导致的生育率低。。

gmatziyu

74题c选项的解释说不过去呢....

cynthia1226

1. 题目说have beenfrequently recollared 的犀牛生育率低，而结论是镇定剂导致生育率低，所以GAP就是镇定剂和recollared, C选项，如果犀牛只在recollared的时候打镇定剂，那么就是这个原因导致生育率低，而如果犀牛还在很多别的时候也打了镇定剂，那么recollared的犀牛生育率低就不一定是因为镇定剂了。。
呃，大概是吧，我以前貌似看过这题，不大记得了，也不知道有没有把结论说反

2. 如果大家都没有意识到加税了，就说明加税不是导致销量下降的原因，应该是WEAKEN
这题选B吧