Question

Body of flatworm is covered by cuticle. Will it be considered as exoskeleton?

Answer 1

Parasitic flatworms (Platyhelminth) possess a cuticle on ectoderm but it is flexible, and free of mineral, thus cannot be considered as exoskeleton.

Explanation:

Exoskeleton and endoskeleton are absent in members of phylum Platyhelminthes. These are the first group of animals where three primary germ layers develop, i.e. ectoderm, mesoderm and endoderm. All members are acoelomate, many are parasitic.

This video shows classroom footage of planaria.