Answer:
I am needed for most animals and hardcover books
In buckles or lace I help set the pace. The farther you go the thinner I grow.
Can not be bought, Can not be sold, Even if it's made of gold. What is it?
Without me everyone would lose their head. What am I?
A man who was outside in the rain without an umbrella or hat didn't get a single hair on his head wet. Why?
I go in hard, come out soft. Blow me hard and I'll make a pop. What am I?