Answer:
You have it even if there is none.
What is something yet nothing, but if you fill it up it will disappear?
It keeps you on the ground and stops things from floating around. What is it?
It is a common and favored clothing material among biker gangs and superheroes.
What can't you see, hear or feel, until itβs too late. What shadows love, and shopkeepers hate?
I am a room that has a roof but no walls. What am I?