Final answer:
The students are engaged in a formal discussion because they are answering a question posed by the teacher and referring to the book as a resource.
Step-by-step explanation:
The students are discussing an academic topic that requires thoughtful preparation. The clue indicating this is that they are answering a question posed by the teacher, who asks them to interpret a specific passage from a book (page 50). Additionally, they bring the book under discussion to use as a resource, referring to a previous page for context.