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问题 选择题

微生物对一个生态系统来说是十分重要的，这是因为（　　）

A．它能直接或间接的以植物为食

B．它能把动植物的遗体和排泄物分解为无机物

C．它能制造有机物

D．它能吸收二氧化碳，放出氧气

答案

微生物有很多种，单细胞的生物都属于微生物，例如：单细胞植物：衣藻，单细胞动物：草履虫，还有细菌真菌．生态系统由非生物成分和生物成分两种，生物成分分为生产者、消费者和分解者；细菌真菌扮演生态系统的分解者，植物扮演生产者，动物就扮演消费者．

A、直接或间接以植物为食的是生态系统的消费者，包括各种动物，故不符合题意．

B、分解者是指细菌和真菌等营腐生生活的微生物，它们能将动植物残体中的有机物分解成无机物归还无机环境，促进了物质的循环，故符合题意．

C、生产者主要指绿色植物，能够通过光合作用制造有机物，为自身和生物圈中的其他生物提供物质和能量，故不符合题意．

D、吸收二氧化碳，放出氧气的主要指绿色植物的光合作用，绿色植物是生态系统的生产者，故不符合题意．

故选：B

阅读理解

The bar-tailed godwit （斑尾鷸）has just broken its own record for the world’s longest non-stop flight, including humans in planes, according to a report made by Lund University Press. The bird can fly non-stop for eight days, while the most impressive man-made airplane can only remain in the sky for 82 hours without a stop.

The bar-tailed godwit’s journey, from Alaska to New Zealand, covers over 6,835 miles. It completes this trip twice a year, in autumn going to New Zealand, and in spring back to Alaska. The tireless bird ends the trip without stopping once for food or rest. All other birds can only finish trips that are twice as short as what the bar-tailed godwit travels.

One reason for the bar-tailed godwit’s success is that it has made the best use of its fuel, which is only 0.41 percent of its body weight over each hour of any given long flight. Hedenstrom, a professor from Lund University, says, “This figure is extremely low compared with other birds.” The bird also has a special body shape that helps it fly easily. It stores body fat and protein to manage its trips. It also travels fast, compared to other birds and animals.

Many questions remain about this bird record holder that never gets lost in the air. Researchers wonder whether it has an inside compass (指南针) that helps it to know the direction. Please watch how beautiful bar-tailed godwits look as they come in for a landing, along with other birds.

小题1:For the flight from Alaska to New Zealand, the bar-tailed godwit__________

A．doesn’t need to stop to eat

B．is afraid of hot weather

C．seems very tired at last

D．should fly less than 7,000 meters小题2:The main reason why the bar-tailed godwit can break the record is that it ______.

A．eats little food every hour

B．has a special body shape

C．stores much water in its body

D．has very light body weight小题3:The last paragraph tells us that _________.

A．researchers have understood the bird very well

B．the bird has a very good sense of direction

C．there are still many who doubt the bird’s ability

D．the bird has an inner compass
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单项选择题

The idea that some groups of people may be more intelligent than others is one of those hypotheses that dare not speak its name. But Gregory Cochran is (1) to say it anyway. He is that (2) bird, a scientist who works independently (3) any institution. He helped popularize the idea that some diseases not (4) thought to have a bacterial cause were actually infections, which aroused much controversy when it was first suggested.

(5) he, however, might tremble at the (6) of what he is about to do. Together with another two scientists, he is publishing a paper which not only (7) that one group of humanity is more intelligent than the others, but explains the process that has brought this about. The group in (8) are a particular people originated from central Europe. The process is natural selection.

This group generally do well in IQ test, (9) 12-15 points above the (10) value of 100, and have contributed (11) to the intellectual and cultural life of the West, as the (12) of their elites, including several world-renowned scientists, (13) . They also suffer more often than most people from a number of nasty genetic diseases, such as breast cancer. These facts, (14) , have previously been thought unrelated. The former has been (15) to social effects, such as a p tradition of (16) education. The latter was seen as a (an) (17) of genetic isolation. Dr. Cochran suggests that the intelligence and diseases are intimately (18) . His argument is that the unusual history of these people has (19) them to unique evolutionary pressures that have resulted in this (20) state of affairs.

5（）

A.Only

B.So

C.Even

D.Hence
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