How did each of the different components of an opera contribute to the drama that was trying to be portrayed?
I will do what I can do: research and quote from a textbook that I used to study from in one of the music history courses I took that taught me largely about the Opera. I also got the chance to watch many operas and study them in-depths and to write about them myself in another course I took when I studied music performance.
The main text you want to locate when getting into this form of music, the "Opera" would be, "A History of Western Music", Sixth Edition by the following authors: Donald J. Grout and Claude V. Palisca. Publishing Company: W.W. Norton & Company, Cit(ies) of publishing: New York and London. Copyright year: 2001.
I have written reference info in case you need to quote from the following answer that I have uncovered from reviewing this text.
From P. 432 of this text, the authors wrote that,
"Many of the stylistic traits associated with the Classic period had their origin in the Italian musical theater of the first decades of the eighteenth century. Because tradition weighed less heavily on comic opera, it was more hospitable to innovations than serious opera." (From the section entitled, "Early Italian Comic Opera), the authors continued to note that, "Opera buffa is one of the terms used in eighteenth-century Italy for comic opera; other terms were dramma giocoso (jocular drama), dramma comico, and commedia in musica. An opera buffa was a full-lengh work with six or more singing characters and, unlike comic opera in other countries, was sung throughout. The comic characters often spoke or sang in a dialect, as they did in some of the Venetian comedies, or the entire play might be in the local dialect, as in Naples. The comic cast was usually complemented by a number of serious characters around whom the main plot revolved and who interacted with the comic characters, particularly in amorous intrigues. The dialogue was set in rapidly delivered recitative that was accompanied by the keyboard only. The arias in the comic operas are made up of short tuneful ...
The dramatic elements of an opera are thoroughly explored and researched in this solution.