Answer:
I go in dry and come out wet. The longer I stay in the stronger my surroundings get.
Drop me and the world will shatter. You can always find me where you empty your bladder.
I am black of eye and bright of hair. I fast into the ground and follow my lord as he races around the world. What am I?
The dirtier I get, the whiter I am. What am I?
I have no voice but I can teach you all there is to know. I have spines and hinges but I am not a door. Once I've told you all, I cannot tell you more. What am I?
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.