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1、智课网TOEFL备考资料托福阅读教材【OG4+delta最新版】分享摘要：在托福阅读备考阶段，OG4和DELTA是我们必不可少的精华材料之一，由于这两本材料里面所展示的题相对于其它材料来说更接近托福阅读真题，使广大考生的热门选择之一。OG4+delta+托福教材版本免费索取啦!吃透OG4+delta+托福教材让我们考前就能了解托福阅读真题，了解托福阅读真题的难易度及答题点等，下面我们还等什么?就跟随小编来看一下吧!托福阅读教材OG17OPPORTUNISTSANDCOMPETITORS(在线测试题)Growth,reproduction,anddail
2、ymetabolismallrequireanorganismtoexpendenergy.Theexpenditureofenergyisessentiallyaprocessofbudgeting,justasfinancesarebudgeted.Ifallofone’smoneyisspentonclothes,theremaybenonelefttobuyfoodorgotothemovies.Similarly,aplantoranimalcannotsquanderallitsenergyongrowingabigbodyifnonewo
3、uldbeleftoverforreproduction,forthisisthesurestwaytoextinction.Allorganisms,therefore,allocateenergytogrowth,reproduction,maintenance,andstorage.Nochoiceisinvolved;thisallocationcomesaspartofthegeneticpackagefromtheparents.Maintenanceforagivenbodydesignofanorganismisrelativelyco
4、nstant.Storageisimportant,butultimatelythatenergywillbeusedformaintenance,reproduction,orgrowth.Thereforetheprincipaldifferencesinenergyallocationarelikelytobebetweengrowthandreproduction.Almostallofanorganism’senergycanbedivertedtoreproduction,withverylittleallocatedtobuildingt
5、hebody.Organismsatthisextremeare“opportunists.”Attheotherextremearecompetitors,”almostallofwhoseresourcesareinvestedinbuildingahugebody,withabareminimumallocatedtoreproduction.Dandelionsaregoodexamplesofopportunists.Theirseedheadsraisedjusthighenoughabovethegroundtocatchthewind,
6、theplantsarenobiggerthantheyneedbe,theirstemsarehollow,andalltherigiditycomesfromtheirwatercontent.Thus,aminimuminvestmenthasbeenmadeinthebodythatbecomesaplatformforseeddispersal.Theseveryshort-livedplantsreproduceprolifically;thatistosaytheyprovideaconstantrainofseedintheneighb
7、orhoodofparentplants.Anewplantwillspringupwhereveraseedfallsonasuitablesoilsurface,butbecausetheydonotbuildbigbodies,theycannotcompetewithotherplantsforspace,water,orsunlight.Theseplantsaretermedopportunistsbecausetheyrelyontheirseeds’fallingintosettingswherecompetingplantshaveb
8、eenremovedbynaturalprocesses,suchasalonganerodi
