This document discusses the characteristics of arthropods and their classification. It begins by defining arthropods as segmented animals in the phylum Arthropoda that have jointed appendages. It then lists key characteristics of arthropods such as a segmented body plan, paired appendages, an exoskeleton, molting, and bilateral symmetry. The document goes on to classify the phylum Arthropoda into 7 classes: Onychophora, Crustacea, Arachnida, Chilopoda, Diplopoda, Trilobita, and Hexapoda (Insects). It provides examples and brief descriptions of each class.