Fun Riddles

Question: All things I devour: Birds, beasts, trees, flowers.
I gnaw iron, bite steel.
I grind hard stones to meal.

What am I?

Question: To give me to someone I don't belong to is cowardly, but to take me is noble.
I can be a game, but there are no winners.

What am I?

Question: In 1940, a correspondent proposed the following question:

A man's age at death was one twenty-ninth of the year of his birth. How old was he in 1900?

Question: To be here is to be close to those dear,
I see no light but feel warmth from within,
it's lonely here but soon I'll be free.

What am I?

Question: I'm number three.
But I'm not a number.
I'm hot and cold at the same moment but not at the same time.
I'm number three.
But I'm not a number.

Who or what am I?