Final answer:
Theme and variations form alters a main theme in each segment by changing melody, harmony, rhythm, or texture, while rondo form repetitively returns to the main theme with contrasting sections in between.
Step-by-step explanation:
The theme and variations and rondo are two forms in music that build upon a single main theme but approach its development differently. The theme and variations form takes the main theme and alters it in various ways across a series of segments, where each variation changes some aspects of the theme, such as its melody, harmony, rhythm, or texture. This can involve embellishments, alterations in speed, mood, or even a complete transformation into a new style. On the other hand, the rondo form follows a more repetitive structure, typically represented as ABACADA, where the 'A' section contains the main theme and recurs throughout the piece. The contrasting 'B', 'C', 'D', etc., sections vary the material, but the focus remains on the return and familiarity of the 'A' theme, giving the rondo a circular or recurring feel.