Answer:
Environmentalists want to keep this from drying.
It goes up and down the stairs without moving.
What is the middle of water but is not an island?
What time starts and stops with an ānā?
What is something you can give away as many times you want without ever losing it?
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.