Answer:
I have fangs and enjoy piecing holes with a single bite.
I have roots nobody sees. I am taller than trees. Up, up I go but I never grow. What am I?
What goes up and down stairs without moving?
I tremble at each breath of air, and yet can heaviest burdens bear. What am I?
I'm found in socks, scarves and mittens. I'm found in the paws of playful kittens. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.