Analyze the following statements about teaching reading through textual genres:

I. It allows learners to understand not only the linguistic structure but also the social purpose of texts.

II. All genres follow a rigid structure and are universally interpreted the same way across cultures.

III. Textual genres promote interaction with diverse discursive practices, supporting literacy beyond grammar.

IV. According to Marcuschi (2008), genres are socio-discursive tools that reflect the communicative practices of communities.

Which ones are correct?