type of digestive system is a kind of characteristic
every_living_human_being has digestive_system digestive_system is system. digestion is anatomical_structure. mammal_digestive_tract is digestive_tract. all_animals has digestive_system digestive_system is not system. digestive_system has liver_and_gallbladder digestive_tract is organ_system. digestive_tract is not organ_system. digestive is substance.