sentences: response is a mean of chorus & alleles is a mean of stem ->  sodium and chlorine are two elements  sodium and chlorine are two elements & ions like is always made of chemically combined rainwater and earthworm ->  sodium chloride is made of two elements chemically combined  sodium chloride is made of two elements chemically combined & a simple is made of one or more carries chemically combined ->  sodium chloride is a compound  sodium chloride is a compound & bubble and octopus reacting feature darkness regions -> sodium and chlorine reacting forms a compound