Answer:
If you lose me you may cause people around you to lose me too.
I make everyone blind. You can't see me but I will always come back for you. What am I?
The faster you run, the harder it is to catch me. What am I?
What five-letter word becomes shorter when you add two letters to it?
Break me and I am better, immediately set and harder to be broken again. What am I?
What goes up the hill and down the hill, And spite of all, yet stand still?