Answer:
I am a cave full of bones and the house of a worm.
Many people own a copy of me. Without me the world would fall.
I go around and in the house but never touches the house
I fill a room but take no space.
The more there is the less you see.
Two brothers we are, great burdens we bear. All day we are bitterly pressed. Yet this I will say, we are full all the day, and empty when go to rest.