In an experiment, a group of pregnant mice were each given food containing minute doses of
the hormone BPA. A control group of pregnant mice were given no BPA. Offspring of mothers
that had been given BPA were 10 percent bigger when weaned from their mothers than were
offspring of mothers in the control group. Clearly, this result supports the hypothesis that the
physical development of mice is significantly affected by prenatal exposure to BPA.
Which of the following is an assumption on which the argument depends?
A. Prenatal exposure of mice to doses of BPA even smaller than those used in the experiment
would not have significantly affected the physical development of the mice.
B. At birth, there was no difference in size between offspring of mothers that had been given
BPA and offspring of mothers in the control group.
C. Postnatal exposure of mice to BPA before the mice are weaned has significant effects on
the physical development of the mice.
D. Exposure of a pregnant mouse to the doses of BPA used in the experiment does not
significantly enhance its ability nurse its offspring.
E. Significant differences in size between offspring of mothers that had been given BPA and
offspring of mothers in the control group persisted long after the offspring were weaned
给的答案选B,但是我怎么都觉得D要更加对一些。求问大大们这个实验到底要控制什么变量呢?
Passage 194
Unlike herbivores and omnivores, predators have traditionally been thought not to balance
nutrient intake because of the assumption that animal tissue as a food source varies little and
is nutritionally balanced. But chemical analysis of invertebrate prey reveals remarkable
variation in nutrient composition among species; even within species, nutrient composition
may vary considerably. Greenstone suggested that predators may select food items according
to their nutrient contents. Jensen et al (2011) have shown experimentally that even sit-andwait
invertebrate predators with limited mobility can work to address nutrient deficiencies. The
wolf spider, for instance, has been shown to regulate nutrient intake by extracting more dry
mass from a prey item if it contains a higher proportion of a nutrient that was deficient in the
previous prey.
2. Which of the following best describes the organization of the passage as a whole?
A. A phenomenon is described, and an interpretation is offered.
B. A claim is made, and the corroborating evidence is evaluated.
C. A hypothesis is presented and undermined by recent findings.
D. A contrast is noted and shown to be specious based on recent findings.
E. A series of assumptions is presented and shown to be based on sound reasoning.
非常感谢!然而其实到现在还是觉得D更对一些。因为文中最后一句
"Clearly, this result supports the hypothesis that the physical development of mice is significantly affected by prenatal exposure to BPA."
"affected by prenatal exposure to BPA" 的对象是小老鼠而不是小老鼠的母亲,所以感觉这个BPA其实并不是作用于小老鼠的母亲使得母亲的喂养能力有提升,而是作用于小老鼠,使得小老鼠的发育速度更快。因而需要排除母亲喂养能力的影响因素,选D。作者: 健人道长 时间: 2018-10-2 20:27:36
阅读机经192确实选B。
我觉得ETS这道题出得不好,因为文章缺少关键信息。
题目来自论文Developmental Exposure to Bisphenol A: Interaction with Endogenous Estradiol during Pregnancy in Mice, American Zoologist, Vol. 40, No. 3 (Jun., 2000), pp. 429-437.
(https://www.jstor.org/stable/388 ... a_info_tab_contents)
我一开始也选了D,但是看了一下论文,有两处对做题有帮助。
1)论文P431讲了实验设计:所有的小鼠出生后,都立刻和亲生母亲隔离,由第三组处于哺乳期的母老鼠喂养。
2)论文P432在阐述results时说:“There were no significant differences in body weight at birth based on intrauterine position or prenatal treatment for either the male or female pups (data not shown).”
结合1)和2),确实选B。 作者: 子湄 时间: 2019-3-2 20:40:13
我今天做到这一题,感觉应该选D啊。文章的结论是受到prenatal exposure to BPA的影响,强调的是怀孕期间接触BPA,但是在断奶之后才测了体重,所以应该排除哺乳期母鼠接触BPA造成的影响。
如果选B的话岂不是否定了出生之前BPA的作用?作者: ba1a糖儿 时间: 2019-5-4 21:45:33