Answer:
What is the thing that stays the same size, but the more it's used the more it decreases?
I'm white, I'm round, but not always around. Sometimes you see me, sometimes you don't.
My first is in blood and also in battle. My second is in acorn, oak, and apple. My third and fourth are both the same. In the center of sorrow and twice in refrain. My fifth starts eternity ending here. My last is the first of last, Oh Dear.
I work when I play and play when I work.
My first is in fish but no in snail. My second is in rabbit but no in tail. My third is in up but not in down. My fourth is in tiara but not in crown. My fifth is in tree you plainly see. My whole a food for you and me.
I can only be played on a windy day
Difficult
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?