its probably dying or sick
It dies.
Nothing, The leg will soon grow back.
Nothing, he's probably molting, so don't disturb him!
So that they can molt in peace. Their life consists of eating "normal food", sleeping, crawling, burrowing, molting, eating "old dead skin", eating "normal food", sleeping, crawling, burrowing, molting, eating "old dead skin".....repeat over & over & over. If their human adds a saltwater aquarium, then they will lay eggs somewhere in that sequence. Otherwise it remains the same life cycle.
Give it another shell to switch in to
This may happen when the rabbit is molting. If the fur turns color and then falls out that is normal.
Crabs are cold blooded animals, as their body temperature rises and falls with their surroundings.
when an object falls is it reactin to the force of gravity?
It can brake.
It falls.
It falls, accelerating constantly until it hits the ground.
It falls and break
Blood volume also falls.