Answer:
I am a box that holds keys without locks, yet they can unlock your soul.
No matter how little or how much you use me, you change me every month.
I am two-faced but bear only one. I have no legs but travel widely. Men spill much blood over me. Kings leave their imprint on me. I have greatest power when given away, yet lust for me keeps me locked away.
What kind of pet always stays on the floor?
I'm full of holes, yet I'm full of water.
I am the kind of an ant that's good at math. What am I?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?