Answer:
People need me, yet they give me away every day. What am I?
I regularly change shape yet remain a sphere. I am always there but not often seen. What am I?
By Moon or by Sun I shall be found. Yet I am undone if there's no light around.
Better touch me before you proceed to second. What am I?
In a tunnel of darkness lies a beast of iron. I can only attack when pulled back. What am I?
Often cooked as fillet, this meat comes from an animal that swims underwater.