Answer:
Facilitating interactivity.
Providing visual variety.
Emphasizing key information.
Explanation:
The judicious use of these elements helps the author in various different ways. These characters facilitate the interaction of the reader with the text by making it easier for him to understand the best way to proceed with the reading. Moreover, they provide visual variety, which makes information easier to process for the reader. Finally, these characters also emphasize key information, helping with reading comprehension.
