What structure is used in nonfiction texts to show an order of events in chronological order?

The structure used in nonfiction texts to show an order of events in chronological order is sequence. This structure organizes information based on the timeline of events, allowing readers to understand the progression and relationship between those events clearly. When a text employs a sequence structure, it typically follows a clear starting point and moves forward in time, detailing how one event leads to another, which helps readers grasp the development of ideas or narratives in a logical manner.

In contrast, the other structures listed serve different purposes: Problem/Solution presents challenges along with strategies for overcoming them, Compare/Contrast examines the similarities and differences between two or more subjects, and Testimonial includes personal accounts to support or illustrate a point. Sequence specifically focuses on ordering events chronologically, making it the most fitting answer for this question.