Name the song by these few lines (my teacher wants to know) Well, gonna write a little letter
Gonna mail it to my local DJ
It's a rocking little record

The song is "Roll Over Beethoven" by The Beatles

Explanation:

dc was afraid of these new companies because they may take their customers away due to them being more better or something else.

i'm not sure i completely understand your question, but i will do my best.

i think the answer you are looking for is sequence. (see below)

a repeated melodic fragment would be best defined as repetition, while repeated chords (different or the same) could be a chord progression. however, you then mentioned the chord and melodic fragment beginning on higher or lower pitches, in that case, the answer could be best defined as a sequence. the definition of a sequence is as follows: "the restatement of a motif or longer melodic (or harmonic) passage at a higher or lower pitch in the same voice."

let me know if this !