He died of 'natural causes'. [=he died because he was ill or old and not by being killed in an accident, battle, etc.]
She was adopted immediately after she was born and never knew her 'natural' [=(more commonly) 'birth'] parents.
a country rich in 'natural resources' [=a country that has many valuable plants, animals, minerals, etc.]
(..) My advice is... Don't ignore the survival skills. Everybody wants to grab a sword but most of you wil die from natural causes. % from infection. % from dehydration. Exposure can kill as easily as a knife. Where's my knife? (..)2012 The Hunger Games