Phylum Arthropoda

General characteristics.

Answer AND Explanation:

They have jointed appendages which serve different functions in different organisms The body is covered by an outer rigid coat called exoskeleton made of chitin. Their bodies are divided into three parts, the head, thorax and abdomen. In some the head and the thorax are fused to form cephalothorax. The digestive system is complete with a mouth, foregut, hindgut and anus. They have an open circulatory system consisting of the heart which pumps blood into hemocoel or blood cavities. Gaseous exchange takes place through trachea, gils or book lungs.