Answer:
I tremble at each breath of air and yet can heaviest burdens bear.
What has keys but no locks a space but no room and you can enter but can't go in?
I can fly but I have no wings. I can cry but I have no eyes. Wherever I go darkness follows me.
By Moon or by Sun, I shall be found. Yet, if there's no light around, I am undone. What am I?
I go up when the rain comes down
They are many and one, they wave and they drum, Used to cover a state, they go with you everywhere.