Answer:
By Moon or by Sun, I shall be found. Yet I am undone, if there's no light around.
What goes around and around the wood, but never goes into the wood?
What has a bottom right at the top?
I am free for the taking. Through all of your life, though given but once at birth. I am less than nothing in weight, but will fell the strongest of you if held.
Sharp and long, flag of the world. What is it?
It produces a flower but it is not its fruit; it produces branches which are its fruit.