Which aspect of the postwar era did jazz’s liveliness

that is true. stravinsky's rite of spring ballet is a prime example of with its focus on prehistoric culture, costumes, and dancing.

including the octave, the answer would 8 notes in a major scale with one note being played twice. ex) c major scale includes: c, d, e, f, g, a, b, c

notice that c is played twice

however, if you were to ask me how many different notes are in a major scale- the answer would be 7.  

violins play the melody in this section of sergei prokofiev's peter and the wolf.

hope this !