Answer:
I dig out tiny caves and store gold and silver in them. I also build bridges of silver and make crowns of gold. They are the smallest you could imagine. Sooner or later everybody needs my help. Yet many people are afraid to let me help them.
There is an ancient invention. Still used in some parts of the world today. That allows people to see through walls.
You heart it speak, for it has a hard tongue. But it cannot breathe, for it has not a lung.
When I'm born I fly. When I'm alive I lay. When I'm dead I run.
A house full, a yard full, a chimney full, no one can get a spoonful.
Almost everyone needs it, asks for it, gives it. But almost nobody takes it.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?