Answer:
I am a cave full of bones and the house of a worm.
In wealth I abound; in water I stand; as a fencer I'm valued all over the land; at Venice I'm famous; by farmers I'm prized; respected by law yet huntsmen despised; consternation and ruin ensue when I break; And the beasts of the forest advantage won't take.
I am the noblest musical instrument
I am in the past never in the future. I don't exist but have existed. I saw what you saw and that is what I will ever see.
He has married many women, but has never been married. Who is he?
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.