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.]
(..) Careful of that hammer. - Dory. - Sea-Monkey has my money. Wake up. Get up. - Come on. - Yes, l'm a natural blue. Get up! Wow. Dusty. The mask. Where's the mask? No! The mask! Get it! Just keeps going on. (..)2003 Finding Nemo