Answer:
I am essential to life on earth! I am split into thirds. Two thirds are the same. One of the thirds is 8. The other two are 1 each.
Turns me on my backs and open up my stomach. You will be the wisest of men though at start a lummox.
Golden treasure I contain guarded by hundreds and thousands. Stored in a labyrinth where no man walks Yet men come often to seize my gold. By smoke I am overcome and robbed then left to build my treasure anew.
I am there when you sit, but gone when you stand. What am I?
I'm really blue but when you see me I'm red. You don't see me too often. I'm there for you if you're hurt.
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.