snails know where they are going because they have a sencer i dont know what it is called but they hear vibrations along the ground, knowing where they are going or if a preditor is around.
Snails are herbovores, and really like lettuce.
All snails that I know of eat algae.
I know its hard to believe, but, ducks do eat snails.
Snails are hermaphrodites; they are both male and female.
do not know
Yes, snails will overpopulate a pond if you let them. It will take a while, but they might. You can bye fish that eat snails, if you want them.
i know that snails have gills i am not sure about the others
I know clams certainly can! I've come across clams in several irrigation jobs. I've never seen snails in mainlines though. I wouldn't put it past those pesky rain jet snails though!
Generally snails are not predators, but there is one species that I know of that is a definite predator. The Assassin Snail, or Clea helena, is a freshwater snails that eats other snails and worms. There are a few other carnivorous snails in the Neogastropoda family also.
i sont know
yes
i don't know what they are allergic to, but i do know that they don't like salt.