Answer:
I am used when you jump off a bridge for fun.
I am round. I have only one line. Circle is not my name indeed. What am I?
What flies without wings?
I sleep when you are awake, I am awake when you fall asleep. I can fly but no feathers to aid my flight. What am I?
I shoot but never kills
A little house full of meat, no door to go in and eat.