Reading Comprehension

[Reading Comprehension] 试题详情

    Even more than mountainside slides of mud or snow, naturally occurring forest fires promote the survival of aspen trees. Aspens' need for fire may seem illogical since aspens are particularly vulnerable to fires; whereas the bark of most trees consists of dead cells, the aspen's bark is a living, functioning tissue that—along with the rest of the tree—succumbs quickly to fire.

    The explanation is that each aspen, while appearing to exist separately as a single tree, is in fact only the stem or shoot of a far larger organism. A group of thousands of aspens can actually constitute a single organism, called a clone, that shares an interconnected root system and a unique set of genes. Thus, when one aspen—a single stem—dies, the entire clone is affected. While alive, a stem sends hormones into the root system to suppress formation of further stems. But when the stem dies, its hormone signal also ceases. If a clone loses many stems simultaneously, the resulting hormonal imbalance triggers a huge increase in new, rapidly growing shoots that can outnumber the ones destroyed. An aspen grove needs to experience fire or some other disturbance regularly, or it will fail to regenerate and spread. Instead, coniferous trees will invade the aspen grove's borders and increasingly block out sunlight needed by the aspens.
The primary purpose of the passage is to explain the

Options:

qualities that make a particular organism unique
evolutionary change undergone by a particular organism
reasons that a phenomenon benefits a particular organism
way in which two particular organisms compete for a resource
means by which a particular organism has been able to survive in a barren region

Correct:

C

Reading Comprehension

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[点此查看答疑][GWD]Reading Comprehension

主旨题,看观点句: 第一段第一句Even more than mountainside slides of mud or snow, naturally occurring forest fires promote the survival of aspen trees. 第二段第一句The explanation is that each aspen, while appearing to exist separately as a single tree, is in fact only the stem or shoot of a far larger organism. 第三句Thus, when one aspen—a single stem —dies, the entire clone is affected. 第5句 But when the stem dies, its hormone signal also ceases. 从而可以看出是一个 particular organism循环往复的过程。 排除法剩下BC比较。 B强调进化着的改变,C强调为什么一个现象能带来好处。B和原文更近,选之
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[点此查看答疑][GWD]Reading Comprehension

答案是C。扫了原文后在AC中犹豫,C中,一下没怎么看出来是哪个phenomenon benifits organism ,而好像一直在说这个ASPEN能怎样。而A中,文中第二段好像确实说ASPEN很独特。但又觉得C,explain reasons 比A explain quality 好。但还是选了A
0评分
170浏览

[点此查看答疑][GWD]Reading Comprehension

主旨题,看观点句: 第一段第一句Even more than mountainside slides of mud or snow, naturally occurring forest fires promote the survival of aspen trees. 第二段第一句The explanation is that each aspen, while appearing to exist separately as a single tree, is in fact only the stem or shoot of a far larger organism. 第三句Thus, when one aspen—a single stem —dies, the entire clone is affected. 第5句 But when the stem dies, its hormone signal also ceases. 从而可以看出是一个 particular organism循环往复的过程。 排除法剩下BC比较。 B强调进化着的改变,C强调为什么一个现象能带来好处。B和原文更近,选之
0评分
85浏览

[点此查看答疑][GWD]Reading Comprehension

答案是C。扫了原文后在AC中犹豫,C中,一下没怎么看出来是哪个phenomenon benifits organism ,而好像一直在说这个ASPEN能怎样。而A中,文中第二段好像确实说ASPEN很独特。但又觉得C,explain reasons 比A explain quality 好。但还是选了A

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