扫描二维码，直接登录
题库 / Prep2012-CR-34
In polluted environments, dolphins gradually accumulate toxins in their body fat, and the larger the dolphin the more accumulated toxins it can tolerate. Nearly 80 percent of the toxins a female dolphin has accumulated pass into the fat-rich milk her nursing calf ingests. Therefore, the unusually high mortality rate among dolphin calves in the industrially contaminated waters along Florida's Gulf Coast is probably the result of their being poisoned by their mother's milk.
Which of the following, if true, most strengthens the argument?
The survival rate of firstborn dolphin calves in the area along Florida's Gulf Coast is highest for those whose mothers were killed before they were weaned.
The rate at which adult dolphins living in the waters along Florida's Gulf Coast accumulate toxins is no higher than that of adult dolphins in comparably polluted waters elsewhere.
Among dolphin calves born in the area along Florida's Gulf Coast, the mortality rate is highest among those with living siblings.
As dolphins age, they accumulate toxins from the environment more slowly than when they were young.
Dolphins, other marine mammals, have a higher proportion of body fat than do most land mammals.
增强？
选项A（√）
The 【survival rate存活率】 of 【firstborn dolphin calves小海豚】 in the area along Florida's Gulf Coast is 【highest 最高】for those whose 【mothers were killed before they were weaned 海豚妈妈在断奶前被杀】.
在佛罗里达州墨西哥湾沿岸地区，那些海豚妈妈在断奶前被杀的海豚幼崽的存活率最高。
= 海豚妈妈死了→ 小海豚还没喝够海豚妈妈的毒奶 → 小海豚体内累积的毒素不够多→ 小海豚还没达到死的标准（所以存活下来）
B 成年海豚身体的毒素在Florida的和其他地方的没差，这个不是support
C：已知
D：讲到了环境对毒素的影响，与母乳传递的无关
E: body fat与母乳传递无关！
说明二者之间有因果关系。
choice a, 同一片区域内，幼崽成活率最高的群体是那些在哺乳之前母海豚就已经死亡的。correct
注意关注结论：结论是母乳导致了calf的高死亡率，强调的是母乳的作用，而不是高污染的环境对于高死亡率的作用。
读懂A选项！
Therefore, the unusually high mortality rate among dolphin calves in the industrially contaminated waters along Florida's Gulf Coast is probably the result of their being poisoned by their mother's milk.
注意关注结论：结论是母乳导致了calf的高死亡率，强调的是母乳的助攻作用，而不是高污染的环境对于高死亡率的助攻作用（很有误导性）
而A选项，意思是，那些在断奶前丧母的幼崽存活率高。断奶前丧母，这表明了他们都没怎么喝奶，或者说喝奶时间比较短，所以存活率高，也就加强了喝污染奶导致死亡。
一词不懂此题就废，Wean断奶