Answer:
What is often returned but is never borrowed?
I am the heart that does not beat. If cut, I bleed without blood. I can fly, but have no wings. I can float, but have no fins. I can sing, but have no mouth.
My life can be measured in hours, I serve by being devoured. Thin, I am quick. Fat, I am slow. Wind is my foe.
What do you fill with empty hands?
When the creeper passes, all the grass kneels
I can be found in water but never wet
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?