Based on the clue 'a water filled barrier around a castle', what is the answer?

What is referred to by 'a watched pnb'? Based on the clue 'a watched pot never does this', what is the answer? Based on the clue 'a watchtower distributors relocation service provi...', what is the answer? Based on the clue 'a water bird related to seagulls we hope you dont ...', what is the answer? Based on the clue 'a water snail has these at the base of its tentacl...', what is the answer? Based on the clue 'a water spirit or to put the kibosh on something', what is the answer? What is associated with: a water tower in stanton iowa has been painted like a giant one of these at over 35000 gal tha… What is associated with: a waterfall on this continent has the longest drop in the world 3212 feet?