Aria , changing Scenery , recitative and costumes are all expected to find as part of an opera.
Opera is a form of theatre in which music has a leading role and the parts are taken by singers, but ir differs from musical theater.
Opera is a fundamental part of the Western classical music tradition. Opera emerged in Italy at the end of the 16th century and soon expanded through the rest of Europe.
This form of theatre has included several genres, including some that include spoken dialogue.