题干

通过对实验现象的观察、分析推理得出正确的结论是化学学习的方法之一。对下列实验事实的解释正确的是(    )

选项

现象

解释

A

KI淀粉溶液中通入Cl2,溶液变蓝

Cl2能与淀粉发生显色反应

B

SO2能使酸性高锰酸钾溶液褪色

SO2具有还原性

C

某溶液中加入硝酸酸化的氯化钡溶液,有白色沉淀生成

该溶液中一定含有SO42

D

铁与稀硝酸反应有气泡产生

铁与稀硝酸发生了置换反应

A:A   

B:B   

C:C   

D:D

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答案(点此获取答案解析)

B

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阅读理解

    How could we possibly think that keeping animals in cages in unnatural environments, mostly for entertainment purposes, is fair and respectful?

    Zoo officials say they are concerned about animals. However, most zoos remain “collections” of interesting “things” rather than protective habitats. Zoos teach people that it is acceptable to keep animals bored, lonely, and far from their natural homes.

    Zoos claim to educate people and save endangered species, but visitors leave zoos without having learned anything meaningful about the animals' natural behavior, intelligence, or beauty. Zoos keep animals in small spaces or cages, and most signs only mention the species' name, diet, and natural range. The animals' normal behavior is seldom noticed because zoos don't usually take care of the animals' natural needs.

    The animals are kept together in small spaces, with no privacy and little opportunity for mental and physical exercise. This results in unusually and self-destructive behavior called zoo-chosis(圈禁性精神病). A worldwide study of zoos found that zoochosis is common among animals kept in small spaces or cages. Another study showed that elephants spend 22 percent of their time making repeated head movements or biting cage bars, and bears spend 30 percent of their time walking back and forth, a sign of unhappiness and pain.

    Furthermore, most animals in zoos are not endangered. Captive breeding(圈养繁殖) of endangered big cats, Asian elephants, and other species has not resulted in their being sent back to the wild. Zoos talk a lot about their captive breeding programs because they do not want people to worry about a species dying out. In fact, baby animals also attract a lot of paying customers. Haven't we seen enough competitions to name baby animals?

    Actually, we will save endangered species only if we save their habitats and put an end to the reasons people kill them. Instead of supporting zoos, we should support groups that work to protect animals' natural habitats.