Short difficult clean riddles for teens

What gets wet while it's drying?

A natural state, I'm sought by all. Go without me and you shall fall. You do me when you spend, and use me when you need to eat to no end.

What king can you make if you take: the head of a lamb the middle of a pig the hind of a buffalo and the tail of a dragon?

Can you find four consecutive prime numbers that add up to 220?

I have more than 80 keys, but I cannot open any lock. What Am I?

I get whiter the dirtier I get. What am I?

It's red, blue, purple and green. No one can reach it, not even the queen.

What you cannot hold it but it is yours?

What has a foot on each side and one in the middle?

I build up castles. I tear down mountains. I make some men blind, I help others to see. What am I?