While professional singers can command a pitch range of two octaves or more, an untrained voice is usually limited to abouta. half an octaveb. one octavec. an ocatve and a halfd. two octaves

If the measure is suppose to have six beats and we need 1 note and 1 rest, we can either do a whole note with a half note rest after that since a whole note equals 4 beats and a half note rest equals 2 beats or we could do a whole note rest with a half note after that since a whole note rest is 4 beats and a half note is 2 beats

Well, the four major ones to use would be contrast, proximity, alignment, and repetition.