Answer:
I have roots nobody sees. I am taller than trees. Up up I go but I never grow.
I run up and down the stairs without moving
You see a boat filled with people. It has not sunk but when you look again you don't see a single person on the boat. Why?
If you have me you want to share me. If you share me you don't have me. What am I?
I am used to bat with, yet I never get a hit. I am near a ball, yet never thrown. What am I?
I am your mother's brother's only brother in law. Who am I?