What is the characteristic of unstable scale degrees in music?

The characteristic of unstable scale degrees in music is that they resolve to another tone or chord. Unstable scale degrees tend to create tension and are often described as needing resolution. For example, in tonal music, the leading tone (the seventh scale degree) is a classic example of an unstable degree because it typically resolves upward to the tonic, creating a sense of movement and direction in the music.

This tension is essential for establishing a narrative or emotional arc within a piece, as the listener anticipates the resolution to a more stable, consonant tone or chord. In contrast, stable degrees, such as the tonic or subdominant, do not carry this tension and often offer a sense of rest or completion.

Other choices reflect characteristics that do not align with the nature of unstable degrees. For example, the concept of remaining unchanged contradicts the very definition of unstable degrees, which are defined by their need to resolve. Similarly, being accompanied by a major triad or providing a sense of completion applies more to stable harmonies and chords that give a feeling of closure rather than the tension found in unstable degrees.