Concept:Arthropods are invertebrates with segmented bodies, jointed appendages, and a chitinous exoskeleton.Explanation:Arthropods do not grow freely; they moult because their exoskeleton is rigid, so A is incorrect.Their bodies are segmented, so C is incorrect.A defining feature is that their body is covered by a chitinous exoskeleton.Therefore, the correct option is D.Answer:D. The body is covered by chitin.