Answer:
What is it that no man ever saw, which never was, but always will be?
How many people are dead in a standard grave yard?
Many foods can make me strong but give me water and I won't last long.
What is the middle of water but is not an island?
Retired people want these to be large and birds want them to hatch.
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.