Final answer:
To support the idea of singing's significance at the March on Washington, the authors reference the use of freedom songs and the presence of influential speakers and musicians, illustrating the unifying and emotive power of music in civil rights advocacy.
Step-by-step explanation:
The authors support the idea that "singing played a big part of the March on Washington" by noting the presence of civil rights movement leaders who often incorporated freedom songs during social protests to emotionally unify participants and symbolize their collective struggle. The March on Washington for Jobs and Freedom is particularly remembered for its use of music, with famous artists such as Mahalia Jackson and Bob Dylan performing, as well as the collective singing of freedom songs by the large crowds gathered at the event. This community's act of singing was a way to convey the message of hope, solidarity, and the desire for civil rights.
Moreover, the figure of Dr. Martin Luther King Jr. addressing an enthusiastic crowd symbolizes the amalgamation of speech and music as powerful instruments for advocacy, which were used effectively during the march. Also, participation of churches in advocating for social change through the civil rights movement reinforces the context in which music, especially gospel music, found its voice in the struggle for equality, showing how deeply intertwined the act of singing was with the movement.