Which organism would be classified as an arthropod?

Phylum Arthropoda is the most diverse and abundant phylum of animals, estimates range from 2 to 10 million species fall into Arthropada.

All arthropods have an exoskeleton made of chitin (pronounced kite-en) which are strong fibers of long nitrogen-containing sugars. Additionally arthropods are the first animals to evolve jointed appendages, hence their name (arthro = jointed, poda = foot or appendage). Arthropods are coelomate, meaning they have an open circulatory system, but their organ systems are well developed.

Examples of arthropods range from lobster, crabs, shrimps, and crayfish, to insects, arachnids (Spiders, scorpions, mites, and ticks), millipedes, and centipedes.