What goes, comes back.

(Teachings from Gita) When you leave this world, you go to heaven. When your time in heaven has expired, you merge into the sky. From there into the wind and from wind into dust. The dust goes into the clouds and clouds fall onto the earth in the form of rain. This water is absorbed by the flora on the earth which is consumed by man in one form or the other other and hence plays a role in the genesis of a new one from the womb of a mother.