Answer:
I have three hundred cattle, with a single nose cord
I'm white, I'm round, but not always around. Sometimes you see me, sometimes you don't.
In buckles or lace, they help set the pace. The farther you go, the thinner they grow.
I bind it and it walks. I loose it and it stops.
Dies half its life. Lives the rest. Dances without music. Breathes without breath.
What an fill a room but takes up no space?
Difficult
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?