Final answer:
The Pony Express is a topic from history, specifically related to United States mail delivery services in the 19th century. It's a subject that can be explored in a history class for its historical significance.
Step-by-step explanation:
The Pony Express is an example of a(n) topic. The Pony Express refers to a mail delivery service that operated in the United States during the 19th century. This historical topic can be the subject of various discussions and assignments in a history class, where students might explore its origins, significance, the challenges faced, and its eventual replacement by the telegraph and other forms of communication.