Australia’sfrogsarehavingtroublefindinglove.Trafficnoiseandother

Australia’sfrogsarehavingtroublefindinglove.Trafficnoiseandothersoundsofcitylife,suchasairconditionersandconstructionnoise,aredrowningoutthematingcallsofmalefrogsinurbanareas,1eadingtoasharpdropinfrogpopulations.But,inthefirststudyofitskind,Parris,ascientistattheUniversityofMelbournehasfoundthatsomefrogshavefiguredoutawaytocompensateforhumaninterferenceintheirlovelives. 　　Amalesouthernbrowntreefrogsendsoutamatingcallwhenhe’slookingforadate.Itismusictotheearsofafemalesouthernbrowntreefrog.But,addthesoundsofnearbytrafficandthemessagejustisnotgoingout.ParrisspentsevenyearsstudyingfrogsaroundMelbourne.Shesayssomefrogshavecomeupwithaninterestingstrategyformakingthemselvesheard. 　　“Wefoundthatit’schangingthepitchofitscall,sogoinghigherup,upthefrequencyspectrum,beinghigherandsqueakier,furtherawayfromthetrafficnoiseandthisincreasesthedistanceoverwhichitcanbeforheard,”Parrissaid. 　　Theoldcallislowerinpitch.Thenewoneishigherinpitch. 　　Now,thatmaysoundlikeaprettysimplesolution.But,changingtheircallstocopewithanoisyenvironmentisactuallyquiteextraordinaryforfrogs.Andwhilethemaleshavefiguredouthowtomakethemselvesheardabovethenoise,Parrissaysitmaynotbewhatthefemalesarelookingfor. 　　“Whenfemaleshaveachoicebetweentwomalescalling,theytendtoselecttheonethatcallsatalowerfrequencybecause,infrogs,thefrequencyofacallisrelatedtobodysize.So,thebiggerfrogstendtocalllower,”sheexplained.“Andsotheyalsotendtobetheolderfrogs,theguysperhapswithmoreexperience,theyknowwhatthey’redoingandthewomenareattractedtothose.” 　　FrogpopulationsinMelbournehavedroppedconsiderablysinceParrisbeganherresearch,butitisnotjustbecauseofnoise.MuchofAustraliahasbeenlockedina10-yeardrought,leavingfrogsfewerandfewerpondstogolookingforthatspecialsomeone. Whydosomefrogschangethepitchofitscalls?

A.To be different from others.

B.To attract a female frog.

C.To tend out messages.

D.To go against traffic noises.

正确答案是D