2. 职称英语
  3. Through a series of experiments, an American scientist has obtained an under

Through a series of experiments, an American scientist has obtained an under

游客2023-07-27  23
问题     Through a series of experiments, an American scientist has obtained an understanding of the social structure of the most complex of ant societies. The ants examined are the only creatures other than man to have given up hunting and collecting for a completely agricultural way of life. In their underground nests they cultivate gardens on soil made from finely chopped leaves. This is a complex operation requiring considerable division of labor. The workers of this type of ant can be divided into four groups according to size. Each of the groups performs a particular set of jobs.
    The making and care of the gardens and the nursing of the young ants are done by the smallest workers.  Slightly larger workers are responsible for chopping up leaves to make them suitable for use in the gardens and for cleaning the nest. A third group of still larger ants do the construction work and collect fresh leaves from outside the nest. The largest are the soldier ants, responsible for defending the nest.
    To find out how good the various size-groups are at different tasks, the scientist measured the amount of work done by the ants against the amount of energy they used. He examined first the gathering and carrying of leaves. He selected one of the size-groups, and then measured how efficiently these ants could find leaves and run back to the nest. Then he repeated the experiment for each of the other size-groups. In this way he could see whether any group could do the job more efficiently than the group normally undertaking it.
    The intermediate-sized ants that normally perform this task proved to be the most efficient for their energy costs, but when the scientist examined the whole set of jobs performed by each group of ants it appeared  that some sizes of worker ant were not ideally suited to the particular jobs they performed. [br] The scientist’s work was based on______.
选项 A、occasional observations
B、systematic observations
C、observations of several nests
D、observations of an undisturbed nest
答案 B
解析 推断题。本题问的是：科学家的研究工作是基于______。仔细分析科学家所做的实验，我们可以看出科学家先是选出一组蚂蚁让它们做搬树叶进洞的工作，然后再让其他三组蚂蚁也做同样的工作，从而考察哪组蚂蚁的工作效率高。接着再让这四组蚂蚁分别做另外三样厂作，最后得出结论，即按个头大小分配工作的方法有时可以获得最高工作效率，有时则不能。这样一个实验过程可以说是按步骤、有条理地进行。故选B 。
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