Answer:
Without a bridle, or a saddle, across a thing I ride a-straddle. And those I ride, by help of me, though almost blind, are made to see. What am I?
You buy me to eat, but never eat me. What am I?
I have a bank, but no money. I have a bed but do not sleep.I have a mouth but cannot eat. What am I?
I dig out tiny caves and store gold and silver in them. I also build bridges of silver and make crowns of gold. Sooner or later everybody needs my help yet many people are afraid to let me help them.
I sleep when you are awake, I am awake when you fall asleep. I can fly but no feathers to aid my flight. What am I?
Give it food and it will live, give it water and it will die.