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.]
(..) I just went into the water. Well, next time it'll be a lot easier. I have to do that again? Yeah, you have to practice several times before the final, but you're a natural. You got nothing to worry about. My whole body was covered in these little insects. They were in my ears, and my throat... (..)2014 Divergent