ly ▁alter ed ▁by ▁human ▁inter vention , ▁or ▁which ▁persist ▁despite ▁human ▁inter vention . ▁For ▁example , ▁manufact ured ▁objects ▁and ▁human ▁interaction ▁generally ▁are ▁not ▁considered ▁part ▁of ▁nature , ▁unless ▁qualified ▁as , ▁for ▁example , ▁" human ▁nature " ▁or ▁" the ▁whole ▁of ▁nature ". ▁This ▁more ▁traditional ▁concept ▁of ▁natural ▁things ▁that ▁can ▁still ▁be ▁found ▁today ▁implies ▁a ▁distinction ▁between ▁the ▁natural ▁and ▁the ▁artificial , ▁with ▁the ▁artificial ▁being ▁understood ▁as ▁that ▁which ▁has ▁been ▁brought ▁into ▁being ▁by ▁a ▁human ▁conscious ness ▁or ▁a ▁human ▁mind . ▁Depending ▁on ▁the ▁particular ▁context , ▁the ▁term ▁" natural " ▁might ▁also ▁be ▁distinguished ▁from ▁the ▁un natural ▁or ▁the ▁super natural . ▁ ▁Earth ▁ ▁Earth ▁is ▁the ▁only ▁planet ▁known ▁to ▁support ▁life , ▁and ▁its ▁natural ▁features ▁are ▁the ▁subject ▁of ▁many ▁fields ▁of ▁scientific ▁research . ▁Within ▁the ▁solar ▁system , ▁it ▁is ▁third ▁closest ▁to ▁the ▁sun ; ▁it ▁is ▁the ▁largest ▁terrest rial ▁planet ▁and ▁the ▁fifth ▁largest ▁overall . ▁Its ▁most ▁prominent ▁clim atic ▁features ▁are ▁its ▁two ▁large ▁polar ▁regions , ▁two ▁relatively ▁narrow ▁temper ate ▁zones , ▁and ▁a ▁wide ▁equ atorial ▁tropical ▁to ▁subt rop ical ▁region . ▁P reci p itation ▁var ies ▁widely ▁with ▁location , ▁from ▁several ▁metres ▁of ▁water ▁per ▁year ▁to ▁less ▁than ▁a ▁mill imet re . ▁ 7 1 ▁percent ▁of ▁the ▁Earth ' s ▁surface ▁is ▁covered ▁by ▁salt - water ▁o ce ans . ▁The ▁remainder