the small intestine is a part of the digestive system
small_intestine_tissue is intestinal_tissue. small_intestine is internal_organ. digestive_tract is internal_body_part. digestive_system is system. digestive_tract is not body_part. small_intestine_tissue_cells is intestinal_cell. digestive_tract is organ_system. digestive_tract is body_part. small_intestine is intestine. small_intestine is not internal_organ.