CWhen an ant dies, other ants take it out of the nest, often within an hour after its deat

C
When an ant dies, other ants take it out of the nest, often within an hour after its death. This behavior interests scientists and they wonder how ants know for sure--and so soon--that another ant is dead.
One scientist recently came up with a way to explain this ant behavior. Dong-Hwan Choe is a biologist, a scientist who studies animals and plants. He found that ants have a chemical on the outside of their bodies that signals to other ants, “I’m dead--take me away” when it is dead.
One scientist recently came up with a way to explain this ant behavior. Dong-Hwan Choe is a biologist, a scientist who studies animals and plants. He found that ants have a chemical on the outside of their bodies that signals to other ants, “I’m dead---take me away” when it is dead.
But there's a question to answer: As we know, if an ant is dead, it stops moving. But when an ant is sleeping or knocked unconscious, it is also not moving. However, other ants don't move the living ant out of the nest. How do they know this ant is not dead? Choe found that ants have another chemical on their bodies, which tells nearby ants something like, “Wait—I'm not dead yet” when it is not dead. Choe suspects that when an ant dies, the chemical that says, “Wait— I'm not dead yet” quickly goes away. When other ants detect the “dead” chemical without the “not dead yet” chemical, they move away the body.
To test his theory, Choe and his team put different chemicals on ants. When the scientists used the “I'm dead” chemical, other ants quickly moved the treated ant away. When the scientists used the “Wait—I'm not dead yet” chemical, other ants left the treated ant alone. Choe believes this behavior shows that the “not dead yet” chemical overrides the “dead” chemical when picked up by other ants. And that when an ant dies, the “not dead yet” chemical fades away. Other nearby ants then detect the remaining “dead” chemical and remove the body from the nest.
Understanding this behavior can help scientists figure out how to stop ants from invading new places and causing problems.
【小题1】What is the function of the first paragraph?A．Leading the following paragraphs.B．Showing the main idea of the passage.C．Introducing the background of the passage.D．Giving a summary of the passage.【小题2】Which of the following has the closest meaning to the underlined word “overrides” in the fourth paragraph?A．is weaker thanB．is stronger thanC．is better thanD．is worse than【小题3】What can we learn from the passage?A．Living ants can also be taken away when they are not moving.B．When an ant dies, it can tell others using a certain chemical.C．A living ant can pretend to be dead using a special chemical.D．Ants often use chemicals to communicate with each other.【小题4】Which of the following descriptions about Dong-Hwan Choe is right?A．Choe did this study in order to stop ants from invading new places.B．Choe is a biologist who is only interested in animals, especially in ants.C．Choe first came up with an idea to explain this ant behavior，and then did some tests to prove his theory.D．Choe did the research on this ant behavior on his own.A

(答案→)A 解析：【文章大意】本文是一篇科普文章。文章讲述了蚂蚁是怎样得知蚂蚁死了，然后把它弄出蚂蚁洞的。文章通过实验研究得知：在死去蚂蚁的身体外面发出一种化学物质，告诉其他蚂蚁“它已经死了”。【小题1】A考查作者的写作意图。文章的第一段提出问题吸引读者，并引出下文科学家要解决的问题。所以第一段起的是统领全文的作用。故选A。【小题2】B考查猜测词义。根据文章第四段中的When the scientists used the “Wait—I'm not dead yet” chemical, other ants left the treated ant alone. Choe believes this behavior shows that the “not dead yet” chemical overrides the “dead” chemical when picked up by other ants.可知，当“I'm not dead”的化学物质超过“I'm dead”的化学物质时，其他蚂蚁才不理这些蚂蚁。故此处overrides是“强于，超过”的意思。选B。【小题3】B考查推理判断。根据文章第二段中的One scientist recently came up with a way to explain this ant behavior. Dong-Hwan Choe is a biologist, a scientist who studies animals and plants. He found that ants have a chemical on the outside of their bodies that signals to other ants, “I’m dead---take me away” when it is dead.可知，蚂蚁死后有一种化学物质给其他蚂蚁发出信号告诉它们“它已经死了”。故选B。其他三项与文章内容不符。【小题4】C考查推理判断。根据文章第二段中的One scientist recently came up with a way to explain this ant behavior. Dong-Hwan Choe is a biologist, a scientist who studies animals and plants. He found that ants have a chemical on the outside of their bodies that signals to other ants, “I’m dead---take me away” when it is dead.可知，Choe先提出理论，然后证实了他的理论。故选C。

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