Answer:
You eat something you neither plant nor plow. It is the son of water, but if water touches it, it dies.
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.
They try to beat me, they try in vain. And when I win, I end the pain.
The land was white the seed was black it'll take a good scholar to riddle me that. What is it?
Twigs and spheres and poles and plates. Join and bind to reason make.
They are many and one, they wave and they drum, Used to cover a state, they go with you everywhere.