Explain the concept of "harmony" in choral music.

Harmony in choral music is fundamentally about the blending of different musical notes that are sung or played at the same time. This combination creates a richer and more complex sound than a single melody could produce alone. When multiple voices or instruments come together in harmony, they create a sense of depth and fullness, enhancing the emotional and aesthetic impact of the music.

In choral arrangements, harmonies can include various intervals and structures, such as major or minor chords, which evoke different feelings and moods within a piece. This interplay of voices allows for dynamic expression, giving rise to moments of tension and resolution as the harmonies shift and develop throughout the composition.

The other choices do not accurately represent the concept of harmony. The rhythm of a single melody pertains to its timing and pace rather than the simultaneous combination of notes, while the speed of a song, referred to as tempo, is unrelated to harmony. Solo performances do not encompass the idea of harmony because they focus on an individual voice rather than the blend of multiple voices that creates harmony.