Answer:
The subheadings tell the audience what type of information is in each section.
Step-by-step explanation:
The main purpose of the subheadings in this example is to guide the reader's interaction with the poster. In this poster, the reader is provided with a lot of different information. However, in order for the experience to be more easily understood, the poster tells the audience what they should expect in each section. This allows the audience to know what to expect, and thus to process the information provided more easily.