题干

图乙表示图甲的反应过程中有关物质浓度随时间变化的曲线,下列叙述正确的是(  )

A:图甲中物质a可以是麦芽糖也可以是乳糖

B:图乙中若曲线①②③表示不同温度下酶促反应速率,则温度曲线①>曲线②>曲线③

C:图甲中物质b能降低该化学反应的活化能,其化学本质与无机催化剂相同

D:图乙中若曲线①②③表示不同酶浓度下酶促反应速率,则酶浓度曲线①>曲线②>曲线③

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D

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    Elephants in Uganda are starting to come close to villages near national parks. The big animals are a real danger to people.

    So, the Uganda Wildlife Authority has been giving people new tools to keep the elephants away: vuvuzelas. They are plastic instruments some fans use at sports events.

    The instruments make a loud sound elephants do not like. The animals leave, and no one is harmed. A spokesperson for the Uganda Wildlife Authority says vuvuzelas work because they do not threaten the elephants. That is important because an elephant that feels threatened is more likely to attack. So far, no one has reported an elephant attacking in answer to a vuvuzela.

    Officials and villagers have tried other ways to stop elephants from coming near farms and houses. They have built beehives – houses for flying insects that sting. They have hung ropes covered in spicy oil. They have dug long, deep holes. And they have used guns, called A-K47s.

    An official from the Uganda Wildlife Authority explains that people shoot the gun in the air to scare the elephant. But over time, the elephants have stopped being afraid of the sound of the gun. They only look at the shooter and wave their ears.

    Another official for the Uganda Wildlife Authority, Gessa Simblicious, says one elephant-prevention solution will not work everywhere in Uganda. And one day, elephants may accept the vuvuzela noise, just as they do the sound of the A-K47.

    But right now, vuvuzelas are an effective, non-violent and fun way to deal with a serious problem.