The calcium that makes the egg shell makes it hard.
Shells are primarily calcium, just like in human and animal bones.
Yes... nothing will happen to your yummy crawfish.
Crawfish do not ever come out of their shell. The shell is a type of exoskeleton.
A turtles shell is a form of armor; it makes it very hard for a predator to bite the turtle.
It's the cellophane.
Im guessing crawfish but then again hermits crabs do have their shell and and big claw.so probally an even fight
It's called 'calcification'
vinegar
The shell is hard.
If you put a fresh uncooked egg into vinegar the hard shell will dissolve leaving just the soft membrane.
Grasshoppers do not have a hard shell.