问题 选择题

健康人每天形成的原尿有150升,而每天排出的尿液只有1.5升,这是由于(   )

A.肾小球的过滤作用

B.肾小管的重吸收作用

C.膀胱对尿液的储存作用

D.小肠的吸收作用

答案

答案:B

题目分析:血液流经肾小球时,血液中的尿酸、尿素、水、无机盐和葡萄糖等物质通过肾小球的过滤作用,过滤到肾小囊中,形成原尿;当原尿流经肾小管时,全部葡萄糖、大部分水和部分无机盐等被肾小管重吸收,这些被重吸收的物质进入包绕在肾小管外的毛细血管中,送回到血液,剩下的水、无机盐、尿素等就形成尿液,因此,一个人一天可以形成150L原尿,可排出的尿却只有1.5L左右.其主要原因是肾小管的重吸收作用.

单项选择题
阅读理解

阅读理解

      Are some people born clever, and others born stupid? Or is intelligence developed by our

environment and our experience? Strangely enough, the answer to these questions is yes. To

some extent our intelligence is given to us at birth, and no amount of education can make a genius

out of a child born with low intelligence. On the other hand, a child who lives in a boring environment

will develop his intelligence less than one who lives in rich and varied surroundings. Thus the limits of

person's intelligence are fixed at birth, whether or not he reaches those limits will depend on his

environment. This view, now held by most experts, can be supported in a number of ways.

     It is easy to show that intelligence is to some extent something we are born with. The closer the

blood relationship between two people, the closer they are likely to be intelligence. Thus if we take

two unrelated people at random from population, it is likely that their degree of intelligence will be

completely different. If, on the other hand, we take two identical twins, they will very likely be as

intelligent as each other. Relations like brothers and sisters, parents and children, usually have similar

intelligence, and this clearly suggests that intelligence depends on birth.

     Imagine now that we take two identical twins and put them in different environments. We might

send one, for example, to a university and the other to a factory where the work is boring. We would

soon find differences in intelligence developing, and this indicates that environment as well as birth plays

a part. This conclusion is also suggested by the fact that people who live in close contact with each other,

but who are not related at all are likely to have similar degree of intelligence.

1. The writer is in favor of the view that man's intelligence is given to him_________.

A. at birth                            

B. through education

C. both at birth and through education      

D. neither at birth nor through education

2. If a child is born with low intelligence, he can_________.

A. become a genius

B. still become a genius if he should be given special education

C. not reach his intelligence in his life.

D. reach his intelligence limits in rich surroundings

3. The example of the twins going to a university and to a factory separately shows_________.

A. the importance of their intelligence    

B. the role of environment on intelligence

C. the importance of their positions      

D. the part that birth plays

4. The best title of the passage can be __________.

A. Surroundings    

B. Effect of education

C. Dependence on Environment    

D. Intelligence