Question

which an external skeleton

Answer 1

external Skelton.
for example all molluscs like prawn,snails,etc

Answer 2

Answer:

An exoskeleton (from Greek έξω, éxō "outer" and σκελετός, skeletós "skeleton") is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton (endoskeleton) of, for example, a human. In usage, some of the larger kinds of exoskeletons are known as "shells".