Answer:
1. Readers can use them to identify main ideas at a glance.
Step-by-step explanation:
Subheadings give the reader a very quick idea of what each section under the subheading may contain. It helps the reader to understand the organization of the text as well. The subheadings do not contain summary information or visual content. And while the reader may inadvertently make a connection to the phrase of a subheading, they are not written with this purpose.