Opera choruses vary in size, from a small group of singers to a large ensemble of over 100 voices. The size of the chorus will depend on the specific opera being performed, and the resources available to the opera company.
Opera choruses are typically made up of professional singers who have undergone extensive training. They must have a strong understanding of music theory and vocal technique, and be able to sing in a variety of styles. Opera choruses also require a high level of teamwork and coordination, as they must be able to blend their voices together to create a cohesive sound.
The opera chorus is an important part of the operatic experience, and can help to make the performance even more enjoyable.