Answer:
to provide additional information about the topic of the text.
Step-by-step explanation:
The purpose of the subtitle is to provide additional information about the topic of the text. A subtitle is a secondary title that accompanies the main title and provides more specific details about the content of the text. It is usually located immediately below the main title and can help to clarify the focus or scope of the text. The subtitle can provide context, clarify the main idea, or expand on the topic of the text. It is often used in academic writing, non-fiction books, and articles to give readers a more detailed understanding of the content before they begin reading.