The correct answer is: "to explain the main idea of a section". Headings in an informative text are used to introduce and summarize the main idea of the section that follows.
The correct answer is "to show the relationship between the ideas presented." Headings in an informative text help organize the content and make it easier for readers to understand the main ideas and how they are connected. Headings act as signposts, guiding readers through the text and indicating the different sections or topics being discussed. By scanning the headings, readers can get a sense of the overall structure of the text and locate specific information they are looking for. It is important to pay attention to headings when reading an informative text as they play a significant role in helping comprehend the content.