random4000
Samuel

Question: Without one or the other both would not exist. what i'm I ?

Question: what is the thing that saves us all but kills so many

Question: many that live deserve death, some die but deserve life

Question: what goes up, but never goes down?

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

What am I?