Final answer:
In ritornello form, as it is used in Vivaldi's concertos, the full orchestra alternates with solo sections or solo instruments.
Step-by-step explanation:
In ritornello form, as it is used in Vivaldi's concertos, the full orchestra alternates with solo sections or solo instruments.
In Vivaldi's concertos, the ritornello form consists of alternating sections called the ritornello and the episode. The ritornello is typically played by the full orchestra, while the episodes feature solo sections or solo instruments. The ritornello sections provide a recurring theme that is restated throughout the concerto, while the episodes showcase virtuosic passages and improvisation.
For example, in Vivaldi's famous Concerto for Violin in A minor (Op. 3, No. 6), the opening ritornello is played by the full orchestra, followed by episodes featuring the solo violin. This alternation between the full orchestra and the solo violin continues throughout the entire concerto.