What is characterized as a development in music based on simple rhythmic and melodic figures that repeat with slight variations?

The characteristic that defines this particular development in music is closely aligned with minimalism. Minimalist music often employs simple rhythmic and melodic figures that are repeated multiple times, with gradual or slight variations introduced throughout the piece. This repetitive structure encourages a meditative state and focuses listeners on the subtle changes as the music unfolds.

Minimalism emerged in the mid-20th century and is well-known for its emphasis on clarity and continuity through these repetitive patterns. Key composers associated with this style include Steve Reich, Philip Glass, and Terry Riley, among others. Their works frequently exemplify these principles, making minimalist music distinctive and easily recognizable.

In contrast, the other categories mentioned have different characteristics. Expressionism focuses on conveying intense emotions through more dissonant harmonies and complex structures. Baroque music, known for its ornate and decorative nature, often involves intricate counterpoint and forms rather than simplicity and repetition. Cubism refers to an artistic movement and does not directly relate to musical development in the same way that minimalism does. Therefore, minimalism is the most accurate description of the development characterized by the use of simple rhythmic and melodic figures that are subject to variations.