Inside the snails shell is it's heart, liver, lungs, kidneys, stomach etc. It's shell is like a storage for it's organs. The snail can also retract into it if it feels threatend/sleepy/hibernating. This may not be corrrect but I think the snail can also preserve it moisture levels to stop it drieing out.
sea turtles
like every other turtles they use their shells for camouflage, to hide, and to protect their selves from praetors.
oxygen & food & shells
Male sea turtles usually have more concave shells and longer tails
what young sea turtles of this species have heart shaped shells
because they are not reuseable like that
A terrapin has a shell because it is a turtle, of course. There are 4kinds of turtles: aquatic turtles, land turtles, terrapins, and sea turtles. All turtles have shells.
you spell thereselfs wrong but they hide in shells
Fish Whales Worms Turtles Stars Shells
Hunting for their eggs and shells will kill them and cause them to be extinct.
they use it to portect them from other animals from eating them.
yes but when handling turtles don't squish their shells be very soft they are fragile