sentences: response is a mean of chorus & sodium is a kind of element ->  sodium and chlorine are two elements  angstrom and hill are one evolution & sodium chloride is always made of chemically combined chlorine and sodium -> sodium chloride is made of two elements chemically combined sodium chloride is made of two elements chemically combined  sodium chloride is made of two elements chemically combined & a compound is made of two or more elements chemically combined -> rot subduction is a simple sodium chloride is a compound  rot subduction is a simple & sodium and chlorine reacting forms sodium chloride -> sodium and chlorine reacting forms a compound