Clams have a considerably tough time closing their "clam hands" under water. They have to heave a big volume of water out of their shells before they can close their "clam hands" can close up. When you get close to a clam they close their "clam hands" quickly because of a reaction to sensitive spots that detect the shadow of a potential predator and they their "clam hands" closer together.
Clams want to give divers a warning of not poking them because it affects their delicate tissues of their mantles. They also want to speak out and tell humans that they do not appreciate people picking them up and throwing them under water. It takes away all of the clams energy and damages the clams tissues and mantles.
Clams have great problems with divers and swimmers putting things inside their shells, otherwise what you know as "clam hands". Once people put things into the "clam hands", they can get them out ever again. Afterput tses wateful materials into the "clam hands" infections start and soon enough the clam disposes everything inside their "clam hands" and they are left as an empty clam on the coral reef. The clams outer shell is still left behind but the clam is dead inside.
Clams have great difficulty with the fact that humans touch them and move them around. This exposes the clam to predators and they may be eatan. Also, this makes the clam fall into another feeding area which deprives it from the sunlight which powers its very existance.
Terrors of the deep, well clams are not but, they are just basically just sedentary sun-loving farmers. So, we would appreciate if your teachers would tell you that we love your company but, "Look but don't touch!" We love your company but we also have to survive ourselves. See you around the coral reef!