Answer:
Set, Backstage, Apron, Pit (or orchestra pit), Proscenium Arch, Crossover Space, Trap Door and Wings.
Step-by-step explanation:
Set, Backstage, Apron, Pit (or orchestra pit), Proscenium Arch, Crossover Space, Trap Door and Wings are the parts that are present on the theater and has a specific use. I want all these parts or components in my theater so that my theater look wonderful and world class. Set is the physical surroundings where the action of a play performed by the actors whereas Backstage is the area behind the set that's not seen by the audience.