Which type of organism is characterized by having jointed appendages, ability to molt, and three sets of fused segments? echinoderms molluscs chordates annelids arthropods?

The members of the phylum arthropoda have jointed legs. the number of jointed legs are variable, may be three pairs as in cockroaches, four pairs in prawns and even hundred pairs in centipedes. Members of this phylum have ability to shed their their exoskeleton(molting) and body is divided into three fused segments - head, thorax and abdomen.

the answer is "a.) well–developed vascular system."

explanation: