Answer:
Crooked as a rainbow, and slick as a plate, Ten thousand horses can't pull it straight.
I go around in circles, but always straight ahead. Never complain, no matter where I am led.
I am mother and father, but never birth or nurse. I'm rarely still, but I never wander.
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 am free for the taking. Through all of your life, though given but once at birth. I am less than nothing in weight, but will fell the strongest of you if held.
People take me on walks and I run and have fun. What am I?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?