Answer:
As a composer develops a musical idea she may use fragmentation as a way to shorten the musical motive.
Step-by-step explanation:
Song composition can start with melody or lyrics, there is no rule. Bands or the solo musician are finding the way the creation process will flow better. However, by defining the lyrics, it is possible to know the tonic of a certain passage and how long each section of the song should last. However, it does not matter whether it is from the lyrics or the melody that the central idea of music will emerge, what matters is that while a composer develops a musical idea, he can use fragmentation as a way of shortening the musical motif.