The process of evolution, (that is natural selection of the fittest) does that for them.
Over time the snails have evolved. this evolution developed structures of the snails body so that it could live under water i.e. a siphon to obtain air without having to leave the safety of water, gills, water vascular system for circulation of oxygen.
Apple snails are freshwater aquatic snails. Garden snails are land snails.Apple snails have lungs and gillsGarden snails have lungs onlyApple snails skin is thin and translucent (with slime)Garden snails skin is thick and leathery (with slime)All apple snails have two sets of antennaeGarden snails have species with one and two sets.
water snails but not regular snails
due to evolution, that's why we are related to many other types of animals around the world. if we didn't have bones, we would probably look like snails.
Sea snails Freshwater snails
Apple Snails will eat other snails if you don't feed them. If you feed them, then they are alright.
Snails do not have bristles. Snails do have a raspy tongue though.
no snails are not harmful.
Snails are invertebrates. :)
snails are hervibores?
the protein from the other snails shells