Answer:
Give it food and it will live, give it water and it will die.
I cost no money to use, or conscious effort to take part of. And as far as you can see, there is nothing to me. But without me, you are dead.
Look into my face and I'm everybody. Scratch my back and I'm nobody.
This thing runs but cannot walk, sometimes sings but never talks. Lacks arms, has hands; lacks a head but has a face.
What has thirteen hearts But no body or soul?
What do angels sing in the shower?