What is the morphological characteristic that evolutionarily approximates the beings of the phylum Annelida to arthropods?
The metameric feature, i.e., the body segmentation in metameres, approximates annelids to arthropods as these animals are segmented beings too. (Bristles present in oligochaete and polychaete annelids are also covered with chitin, the similar substance of the arthropod exoskeleton.)