Answer:
I build up castles. I tear down mountains. I make some men blind, I help others to see. What am I?
Everyone has me except for a few. You may not be able to identify me but I can always identify you. What am I?
When I am alive, people sing. When I am dead, people clap hands. What am I?
Wind and cord combine, buzzing in the box. In all this we find, though to some the use is lost. What am I?
I saw the dead bring forth the living. I saw the living bring forth the dead. What did I see?
The warmer I am the fresher I am.