What are Arthropods?

What are Arthropods:

Arthropods are one of the largest phylums in the animal kingdom that make up about 80% of the animal kingdom in population and over 1 million species. The arthropod phyla has a good variety of species ranging from spiders, mites, insects, centipedes, millipedes, to even crabs. But why might an insect be related to an aquatic animal like a crab? All arthropods have the same main appendages: Head, Thorax, Abdomen, and a tough exoskeleton which is how they are related. Their movement and defense varies from species to species.