Q.
The member of this Phylum are terrestrial or aquatic having an organ system level organisation bilaterally symmetrical, triploblastic, segmented and eucoelomate animals?
The body od arthropoda is Bilateral, Triploblastic with organ system level of organization. Head is distinct with high degree of caphalization, consists of many fused segments bears well developed sense organ such as eyes, compound eyes, antennae. Arthropoda have various shapes with externally segmented body. Segmentation is either two region head and trunk or cephalothorax and abdomen or three region with head, thorax and abdomen. Some or all segments bear jointed appendages. Hence name Arthro - joints, poda - foot. No internal segmentation like Annelida. Body wall consists of cuticle composed of protein and polysaccharide chitin which is further strengthened by deposition of mineral (calcium phosphate and carbonate).