useless trivia: What Word Means: Yields?

Questions

Upon what instrument was Pablo Casals a virtuoso?

For which trio of solo instruments did Beethoven write his TripleConcerto in C maior?

What does the indication Da CaPo mean?

Beethoven's Sonata in F major for Violin and Piano, Op. 24 bearswhich seasonal nickname?

Two composers who concentrated on writing opera were both bornin 1813. Who were they?