Which of the following is true about a blues scale?

The blues scale is characterized by its unique combination of notes, including the root (1), a flattened third (b3), and a fifth (5). This distinctive structure helps create the signature sound associated with blues music, which often conveys a feeling of melancholy or expressiveness.

The inclusion of the flattened third is particularly important, as it contributes to the scale's "bluesy" quality, setting it apart from the major pentatonic scale, which uses a natural third instead. The other intervals commonly included in a blues scale are the fourth (4) and the flattened seventh (b7), forming a scale that effectively expresses the emotional depth found in blues music.

The other options do not capture the essence of what defines a blues scale. For instance, the notion that it consists solely of half steps is inaccurate, as the scale contains both half and whole steps in its construction. Additionally, while blues music can be played at various tempos, it is not restricted to a fast tempo; it encompasses a wide range of tempos that align with its expressive qualities. Lastly, the blues scale does indeed include flat notes, specifically the flattened third and the flattened seventh, contradicting the assertion that it lacks any flat or sharp notes.