sentences: the skeletal system is a kind of body system & the muscular system is a kind of body system ->  the muscular system and the skeletal system are both kinds of body systems  the muscular system and the skeletal system are both kinds of body systems & a body system is a part of the body ->  the muscular system and the skeletal system are parts of the body  the muscular system and the skeletal system are parts of the body & the nervous system is used for controlling the body ->  the nervous system can be used for controlling the muscular and skeletal systems  the nervous system can be used for controlling the muscular and skeletal systems & the interaction of the skeletal and muscular systems produces locomotion ->  the interaction of the skeletal and muscular systems to produce locomotion is controlled by the nervous system  the interaction of the skeletal and muscular systems to produce locomotion is controlled by the nervous system & to control something can mean to coordinate something -> the interaction of the skeletal and muscular systems to produce locomotion is coordinated by the nervous system