What Are The Similarities And Differences Between Opera And Oratorio?

What Are The Similarities And Differences Between Opera And Oratorio? Like an opera, an oratorio includes the use of a choir, soloists, an ensemble, various distinguishable characters, and arias. However, opera is musical theatre, while oratorio is strictly a concert piece—though oratorios are sometimes staged as operas, and operas are sometimes presented in concert form.