Answer:
You must keep this thing. Its loss will affect your brothers. For once yours is lost, it will soon be lost by others.
What has roots that nobody sees, and is taller than trees. Up, up it goes, and yet it never grows.
What is often returned but is never borrowed?
What has a mouth but can't chew?
It's usually found dried, but often kept slicker. Above another need, it's said to be thicker. What is it?
You use it between your head and your toes, the more it works the thinner it grows.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?