Answer:
C. All have an exoskeleton
Explanation:
Crustaceans is a subphylum
of Arthropoda. The study of crustaceans is knows as carcinology or crustaceology.
They are important sources of food and they consist of crabs, crayfish, prawns etc. They are closely related to insects in terms of morphological(structural) features.
Crustaceans have varying numbers and structure of appendages. However they lack endoskeletons and possess exoskeletons.
