Answer:
Always in you, sometimes on you. If I surround you, I can kill you. What am I?
Born in the ocean and white as snow. When I fall back to water, I disappear without a trace. What am I?
I go up and down at the same time. Up towards to sky and down towards the ground
What is black and white and red all over?
I'm orange when long I'm white when short. What am I?
No matter how little or how much you use me, you change me every month.