Which section of sonata form presents two or more contrasting themes?

The exposition section of sonata form is where two or more contrasting themes are presented. This part is crucial as it introduces the primary material of the sonata. Typically, the first theme is presented in the home key, and the second theme, which contrasts the first in melody, rhythm, or key, is introduced in a different key. This contrast sets up the tension that drives the rest of the movement.

The development section follows the exposition and is characterized by the manipulation and exploration of the themes introduced earlier, often leading to more complex interactions between them. The recapitulation then brings back the original themes presented in the exposition but resolves them in the home key, while the coda serves as a concluding section, often summarizing the themes without introducing new ones.

Thus, the exposition is essential for setting the thematic foundation of the piece, highlighting its role as the section where contrasting themes are first aired.