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问题 实验题

下表是几种生物细胞色素C与人细胞色素C的组成差异，请分析表中数据后回答：

 

动物名称

黑猩猩猴马鸡金枪鱼酵母菌
与人细胞色素C的差异数0112132144
从上表可知：亲缘关系越近的生物，细胞色素C的差异越              。这一结论的得出是运用了科学探究常用的               法。

答案

小   比较

题目分析：比较法是通过观察，分析，找出研究对象的相同点和不同点，它是认识事物的一种基本方法，是研究动物行为的主要方法，通过上表数据的比较可知：人类与黑猩猩亲缘关系最近，细胞色素C的差异最小是0，人类与酵母菌的亲缘关系最远，细胞色素C的差异最大是44，说明亲缘关系越近的生物，细胞色素C的差异越小。

单项选择题

疟疾的周期性发作，其间歇期的长短取决于（）

A.感染性子孢子进入人体血循环的数量

B.子孢子在肝细胞内发育成裂殖体的时间

C.裂殖体在红细胞内发育成熟的时间

D.裂殖子在红细胞内的数量

E.疟疾虫毒力强弱
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单项选择题

"What does the middleman do but add to the price of goods in the shops " Such remarks are aimed at the intermediate operations between manufacturers and final customers. This practice usually attracts a lot of attention from the public and the press and the operation most talked about is what is often called wholesaling.The wholesaler buys goods in large quantities from the manufacturers and sells them in smaller parcels to retailers, and for this service his selling price to the retailer is raised several percent higher. But his job is made more difficult by retail demand not necessarily running level with manufacturers’’ production. Because he adjusts or regulates the flow of goods by holding stock until required, he frees the manufacturer, to some extent, from the effect on production of changing demand and having to bear the whole risk.The manufacturer can then keep up a steady production flow, and the retailer has no need to hold heavy stocks, who can call on the wholesaler for supplies any time. This wholesale function is like that of a valve in a water pipe. The middleman also bears part of the risk that would otherwise fall on the manufacturer and also the retailer.The wholesaler provides a purely commercial service, for which he is too well rewarded. But the point that is missed by many people is that the wholesaler is not just someone adding to the cost of goods. It is true one could eliminate the wholesaler but one would still be left with his function: that of making sure that goods find their way to the people who want them.

Which of the following statements is true

A．People cannot do without the wholesaler’s function.

B．The function of the wholesaler does not add to the cost of goods.

C．The wholesaler helps to reduce the price of goods in shops.

D．The wholesaler is well paid for his commercial service.
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