the breaking down of food into simple substances occurs in the digestive system
if digest occurs then consume occurs. digestive_system has mouth_and_salivary_glands if metabolize occurs then digest occurs. breaking_down is bodily_function_event. rootage is system. digestive_system is system. digestive is not substance. digestive_system has not do_with_food digestive_system has do_with_food digestive is substance.