Final answer:
The least likely way in which chapters of a fifth grade history textbook might be organized is alphabetically.
Step-by-step explanation:
The least likely way in which chapters of a fifth grade history textbook might be organized is alphabetically. History textbooks typically follow a chronological approach, presenting events in the order they occurred over time. They may also be organized thematically, grouping together related topics or concepts. Geographically organizing chapters would involve discussing events or developments in different regions or countries. Alphabetical organization is not commonly used in history textbooks.