1.Presence of notochord that gives them skeletal support this also develops into between Column in vetertebrates.
2.presence of dorsal hollow nerve cord that develops into the brain and spinal cord which is the nervous system. develops into the central nervous system
3.presence of pharyngeal slit that develops into gills in some aquatic organism and its develops into jaw in some mammals. The gills is use for removal of water that enters the mouth while feeding.
