文档介绍:TheEarth'sAtmosphereUnlessit'srainingorthewindisblowing,wedon'tusuallypaymuchattentiontotheatmosphere,,withouttheatmosphere,theEarthwouldbeadesolate(荒芜的)withnosignsoflife!,theatmosphereprovidesthethreegasesnecessaryforlife:oxygen,nitrogen,,includingourselves,,neon,helium,,theatmospherealsoprotectsusfrommostofthesun'shigh-energyultravioletlightrays,,,99percentofallultravioletraysareabsorbedbeforetheyreachtheEarth',calledozone,',mendthatpeoplelimittheamountoftimetheyspendindirectsunlightandwearasuntanlotion(防晒油),,,theatmosphereregulatesthetemperatureontheEarth'',carbondioxidegasintheatmospherecontrolstheamountofwarmthontheEarth'ssurfacethatisallowedtoradiate(发散),theatmosphereregulatestheEarth'?