问题 选择题

已知物种A的化石比物种B的化石出现晚,那么(    )

A.物种A比物种B的数量多

B.物种A结构比物种B结构复杂

C.物种B由物种A进化而来

D.物种B比物种A高等

答案

答案:B

题目分析:化石在地层中出现的顺序,是人们研究生物进化的一个重要的方面,不同生物化石的出现和地层的形成,有着平行的关系,也就是说,在越古老的地层中,挖掘出的化石所代表的生物,结构越简单,分类地位越低等,水生生物的化石也越多,在距今越近的地层中,挖掘出的化石所代表的生物,结构越复杂,分类地位越高等,陆生生物的化石也越多,这种现象说明了生物是由简单到复杂、由低等到高等、由水生到陆生逐渐进化而来的,另外,科学家还发现在最古老的地层中是没有化石的,说明地球上最初是没有生命的,如图是按年代依次形成的地层,其中物种A化石存在于最新近形成的地层,物种B化石存在于古老的地层中,所以物种A比物种B复杂、高等,故选B。

单项选择题
单项选择题

Personality is to a large extent inherent. A-type parents usually (1) A-type offspring. But the environment must also have a profound effect (2) if competition is important to the parents, it is (3) to become a major factor in the lives of their children.

One place where children (4) A characteristics is school, which is, (5) its very nature, a highly competitive institution. Too many schools (6) the "win at all costs" moral standard and measure their success by sporting achievements. The current (7) for making children compete against their classmates or against the (8) produces a two-layer system, in which competitive A types seem in some way better than their B type fellows. Being too (9) to win can have dangerous consequences: remember that Pheidippides, the first marathon runner, (10) dead seconds after saying. "Rejoice, we conquer!"

(11) the worst form of competition in schools is the disproportionate emphasis on examinations. There is, for example, a (12) school that allows pupils to concentrate on those things they do well. The (13) of competition by examination are somewhat questionable, but competition in the certain (14) of failure is positively harmful.

(15) , it is neither practical nor desirable that all A youngsters change into B’s. The world needs types, and schools have an important duty to try to (16) a child’s personality to his possible future employment. It is top management.

If the preoccupation of schools with academic work was (17) , more time might be spent teaching children surer values. Perhaps selection (18) the caring professions, especially medicine, could be made less by good grades in chemistry and more by such (19) as sensitivity and sympathy. It is surely a mistake to choose our doctors exclusively from A type stock. B’s are important and should be (20) .

17()

A.augmented

B.lessened

C.increased

D.boosted