trees, bushes, mud,
mudd Animals such as alligators are put in moats so eniemies cant get across
I think that the 'trench' you are thinking of is a moat. You could say that it is a trench full of water that surrounds the castle. If you are not thinking of a moat then I am sorry.
Advantage of a water moat
air
Photosynthesis needs sunlight & carbon dioxide besides water
The water-filled trench around a castle is called a moat.
water
Besides these Energy is produced.
What building has a drawbridge and a moat? Simply the answer is a castle, what else does anyway. Only thing I could think of!
Many gases, such as helium.
bones and meat
A moat is a water-filled ditch around a castle. thta is nasty nd and u have to take a shower four a couple of days nd then if u fall in a moat u can die nd i am being do serrouse