Adult female rats who have never beforeencountered rat pups will start to show maternal behaviors after being confinedwith a pup for about seven days. This period can be considerably shortened bydisabling the female’s sense of smell or by removing the scent-producing glandsof the pup.
Which of the following hypotheses bestexplains the contrast described above?
(A) The senseof smell in adult female rats is more acute than that in rat pups.
(B) The amountof scent produced by rat pups increases when they are in the presence of afemale rat that did not bear them.
(C) Female ratsthat have given birth are more affected by olfactory cues than are female ratsthat have never given birth.
(D) A femalerat that has given birth shows maternal behavior toward rat pups that she didnot bear more quickly than does a female rat that has never given birth.
(E) Thedevelopment of a female rat’s maternal interest in a rat pup that she did notbear is inhibited by the odor of the pup.
Researchers have found that when veryoverweight people, who tend to have relatively low metabolic rates, lose weightprimarily through dieting, their metabolisms generally remain unchanged. Theywill thus burn significantly fewer calories at the new weight than do peoplewhose weight is normally at that level. Such newly thin persons will,therefore, ultimately regain weight until their body size again matches theirmetabolic rate.
The conclusion of the argument abovedepends on which of the following assumptions?
(A) Relativelyfew very overweight people who have dieted down to a new weight tend tocontinue to consume substantially fewer calories than do people whose normalweight is at that level.
(B) Themetabolisms of people who are usually not overweight are much more able to varythan the metabolisms of people who have been very overweight.
(C) The amountof calories that a person usually burns in a day is determined more by theamount that is consumed that day than by the current weight of the individual.
(D) Researchershave not yet determined whether the metabolic rates of formerly very overweightindividuals can be accelerated by means of chemical agents.
(E)Because of the constancy of their metabolic rates, people who are at theirusual weight normally have as much difficulty gaining weight as they do losing it。
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发表于 2009-11-7 00:00:26
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