monument to the heroic ideals of New England life, which are jeopardized in the present just as the statue itself is shaken by urban renewal.Images of black children entering segregated schools reveal how the ideals for which Shaw and his men died were neglected after the Civil War. The poem’s final stanzas return to the aquarium. The poet pictures Shaw riding on a fish’s air bubble, breaking free to the surface, but in fact, the aquarium is abandoned and the only fish are fin-tailed cars.This poem is a brilliant example of Lowell’s ability to link private turmoil to public disturbances. The loss of childhood in the early section of the poem expands to the loss of America’s early ideals, and both are brought together in the last lines to give the poem a public and private intensity.The poem is organized into unrhymed quatrains of uneven length, allowing a measure of flexibility within a formal structure.
This poem signifies the heart of america. though the “carols” whitman hears, he notices the people in the background that make america what it is. the laborers, the people who work hard to do a job people don’t think much about; but without them, america would not be what it is now. whitman is also saying how each and every person is connected, related through song, because no matter what you do or where you come from, song is universal. they are all singing to show that they are different, but unified. they are brought together by song. and with all these songs, comes the song of america. when whitman says “each singing what belongs to him or her and no one else,”' he means that every person is living their own life. every life converges to make the “varied carols” he hears when “america is singing.”
Answer:
Because it helps you find the reason for the plot, setting, characters, etc
I think the answer is the 2nd statement : It engages the audience and call for a response.
Hope this help!