Exoskeleton
No, crustaceans have exoskeletons (skeleton on the outside of the body).
Krill is in fact a type of crustacean. Whales are typically animals that consume large amounts of the crustacean krill.
Crayfish have an external skeleton and starfish have an internal skeleton relying on a water vascular system for movement.
A crab
That depends on the type of crustacean in question; it varies between species.
No, prawns is definatly not a fish it is a type crustacean like crab, lobster and shrimp.
They have a type of skeleton called a hydrostatic skeleton. This type of skeleton is a fluid filled sac which is surrounded by muscles.
An octopus or squid
Internal Skeleton
internal skeleton
a sponge skeleton
it doesn't have a skeleton