What Am I Riddles

Question: I'm in every room, yet outside. I move at different paces, but you never see me moving. Where ever I am its crowded, but when your there you don't see or feel anyone. If you try to hit me you always miss, yet you always feel me. You need me to live, but I cause disasters. What am I?

Question: Round like a apple deep like a cup yet all the kings horses can’t pull it up.

Question: When people cut me, I do not bleed. They use me, but then they leave. I die, but then revive. I change my appearance as time goes by. What am I?

Question: What's yours but people use it more then you?

Question: What's wet and dry Takes you low Moves real fast And kills you slow ?