基本信息
文件名称:该段落主要目一个gmatpassage 1.pptx
文件大小:234.79 KB
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更新时间:2025-06-10
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文档摘要

1.Theprimarypurposeofthepassageistoargueagainstaconventionalexplanationfortheextinctionofcertainsalmonpopulationsandsuggestanalternativecorrectacommonmisunderstandingaboutthebehaviorofsalmoninresponsetoenvironmentaldegradationcausedbyhumanactivitycomparetheeffectsofhumanactivityonsalmonpopulationswiththeeffectsofnaturaldisturbancesonsalmonpopulationsdifferentiatetheparticulareffectsofvarioushumanactivitiesonsalmonhabitatsdescribehowenvironmentaldegradationcancausechangesinsalmonpopulationsthatextendbeyondanumericalreduction

2.Itcanbeinferredfromthepassagethattheoccasionalfailureofsomesalmontoreturntotheirnatalstreamsinordertospawnprovidesamechanismbywhich pristinestreamsthatarenearpollutedstreamsepollutedthemselvestheparticularadaptationsofapollutedstream’ssalmonpopulationcanbepreservedwithoutdilutionthenumberofsalmoninpristinehabitatsdecreasesrelativetothenumberinpollutedstreamsanenvironmentallydegradedstreamcouldberecolonizedbynewsalmonpopulationsshouldthestreamrecovertheextinctionofthesalmonpopulationsthatspawninpollutedstreamsisaccelerated

3.Accordingtothepassage,humanactivityhashadwhichofthefollowingeffectsonsalmonpopulations?AnincreaseinthesizeofsalmonpopulationsinsomepreviouslypollutedriversAdeclineinthenumberofsalmoninsomeriversAdecreaseinthenumberstrayingsalmoninsomeriversAdecreaseinthegeneflowbetweensalmonpopulationsthatspawninpollutedstreamsandpopulationsthatspawninpristinestreamsAdeclineinthevulnerabilityofsomesalmonpopulationstotheeffectsofnaturallyoccurringhabitatdestructionWeixin:zhbfree赵洪波/zhaohongbo

4.Theauthormentionsthe“aftermathoftheMountSaintHelenseruption”mostlikelyinordertoprovideanexampleoftheprocessthatallowstherepopulationofriverswhoseindigenoussalmonp