What do all arthropods possess?

All arthropods possess jointed appendages and a distinct body plan that includes three main parts: the head, thorax, and abdomen. This characteristic is fundamental to the classification of arthropods, which is the largest phylum in the animal kingdom and includes insects, arachnids, crustaceans, and myriapods.

The jointed appendages allow for a range of movements and adaptability to various environments, while the three body segments play specific roles in the organism's function – the head typically houses sensory organs and mouthparts, the thorax is involved in locomotion and contains the legs and, in some cases, wings, and the abdomen usually contains the reproductive and digestive systems.

In contrast, not all arthropods have wings, as wings are primarily seen in certain classes like insects. Additionally, while arthropods do have a nervous system, their brains are not necessarily highly developed compared to other groups. Lastly, though they do possess hard exoskeletons made of chitin, this feature alone does not encompass the defining characteristics of all arthropods. Thus, the presence of jointed appendages and the three-part body structure are the definitive traits that all arthropods share.