Answer:
I'm not a bird but I can fly through the sky. I'm not a river but I'm full of water.
I am a protector of the scoreboard.
Without me everyone would lose their head.
A young man wants to have me but when he has me he no longer wants me. Blade in hand he attacks me and does his best to remove me. Yet he knows that it is all in vain.
Before Mt. Everest was discovered what was the highest mountain in the world?
Give it food and it will live, give it water and it will die.