Why is it significant that “the star spangled banner” was written during a time of war

Since "The Star Spangled Banner" was written during a time of war, it was easier for others to understand and feel the emotions of the song. It also allowed the one who wrote the song to be able to convey their emotions into the song.

its about the war and describes wat the writer saw

sentence lenght varies according to word choice.you select which word to use and that will require to use other expressions that collocate with the word chosen.sentence length will vary   according to the choice of words you make to express your ideas.