Answer:
It goes up and down the stairs without moving.
How many bricks does it take to complete a building made of brick?
What is not a ball but yet a sphere, and holds all lands and people year after year?
I am neither a guest nor a trespasser in this place. I belong that belongs to me. Where is it?
Without this, H2O would just be 2O
I am the fountain from which no one can drink. For many I am considered a necessary link. Like gold to all I am sought for, but my continued death brings wealth for all to want more.