Answer:
By Moon or by Sun I shall be found. Yet I am undone if there's no light around.
I have a head tail but no arms and legs.
What gets whiter the dirtier it gets?
I eat I live.I breathe I live. I drink I die.
What is so fragile that saying its name breaks it?
I am used for light yet I am solid. Without me you would feel enclosed. I hate being touched especially with a lot of force. I like to be in buildings.