ManandHisEnvironment(人和环境)throughouthistorymanhaschangedhisphysicalenvironmentinordertoimprovehiswayoflife.withthetoolsoftechnologyhehasalteredmanyphysicalfeaturesoftheearth.hehastransformedwoodlandsandprairiesintofarmsandmadelakesandreserviorsoutofriversforirrigationpurposesorhydroelectricpower.manhasalsomodifiedthefaceoftheearthbydrainingmarshesandcuttingthroughmountainstobuildroadsandrailways.however,man`schangestothephysicalenvironmenthavenotalwayshadbeneficialresults.today,pollutionoftheairandwaterisanincreasingdangertothehealthoftheplanet.eachdaythousandsoftonsofgasescomeoutoftheexhaustsofmotorvehicles.smokefromfactoriespollutestheairofindustrializedareasandthesurroundingareasofthecountryside.thepollutionofwaterisequallyharmful.thewholeecologicalbalanceoftheseaisbeingchangedandindustrialwasteshavealreadymademanyriverslifeless.nowenvironmentalprotectionismorepressingthaneverbefore.asweknow,massivedestructionofenvironmenthasbroughtaboutnegativeeffectsandevenposesagreatthreattoman`sexistence.indifferencetotheseproblemswillmeancommittingsuicide.therefore,effectivemeasuresshouldbetakenandlawspassedtoconserveenvironment.otherwise,maniscertaintosufferfromtheseriousconsequencescausedbythislackofcareforhislivingsurroundings.