And thinking about adjective agreement and making nouns plural, how would you make the following plural: la Comedia, popular.
To make the noun "la Comedia" plural, you would change it to "las Comedias."
As for the word "popular," which is an adjective, it does not have a plural form in Spanish. However, if used to describe a plural noun, the adjective will agree in number and gender with the noun. For example, if you want to say "popular comedies," you would say "comedias populares."