Answer:
What can be heard and caught but never seen?
What is bought by the yard by is worn by the foot?
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.
The sharp slim blade, that cuts the wind. What is it?
When the horse strokes the cat, the wood begins to sing.
I have two eyes in the front and a lot of eyes on my tail
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?