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.]
(..) did pour the leperous distilment Whose effect holds such an enmity with blood of man that, swift as quicksilver... ...it courses through the natural gates and alleys of the body, and with a sudden vigour... ...it doth posset and curd, like acid dropping into milk, the thin and wholesome blood (..)2015 Hamlet
(..) from me whose love was of that dignity... ...that it went hand in hand even with the vow I made to her in marriage And to decline upon a wretch whose natural gifts were poor to those of mine But soft, methinks I scent the morning air. Brief let me be Sleeping within my orchard, (..)2015 Hamlet