sentences: blood is a part of the circulatory system
docs: circulatory_system is body_part. mammal_circulatory_system is circulatory_system. circulatory_system is vascular_system. circulatory_system is internal_body_part. systemic_circulation is circulation_of_blood. circulatory_system is organ_system. blood is body_part. mammal_circulatory_system is body_part. vertebrate_circulatory_system is body_part. blood_vessel is circulatory_conduit.