Choir
You create a presidential music movement by forming a choir of the best singer in the country and singing patriotic songs.
A choir singing in alternation is when different groups or sections of the choir take turns singing parts of a song or piece of music.
Both are used, but "massed choir" removes the confusion with a choir singing a mass.
The saying is "Preaching to the choir."
Choir/gospel choir
There will be a choir singing in church on Sunday.
A Choir Director or professor.
A 'Choir' are a group of singers singing songs. Therefore a church choir are those members of the congregation who come together to practice singing the church music so that they can lead the congregation in singing praises to god.
Yes, Laura Ingalls Wilder was a member of the church choir in her community. She enjoyed singing in the choir and found comfort and joy in singing hymns with others.
singing
Practice singing, try out for the choir, and accept if offered a spot.