nerves are made of nerve cells & the nervous system contains nerves ->  the nervous system contains nerve cells  the nervous system contains nerve cells & nerve cells conduct messages in the body ->  the nervous system conducts messages in the body  the nervous system conducts messages in the body & messages in the body are observations in the form of electrical signals ->  the nervous system conducts observations in the form of electrical signals in the body  the nervous system conducts observations in the form of electrical signals in the body & something that conducts electricty can send electricity somewhere ->  the nervous system sends observations in the form of electrical signals to the rest of the body  the nervous system sends observations in the form of electrical signals to the rest of the body & a body system is a part of the body -> the nervous system sends electrical signals to the other body systems