This Big History LibGuide was made for ninth graders researching how agriculture was fundamental to the development of civilizations. It includes documents, maps, images, and links at a variety of different levels.

• If you are just starting on a topic, pick an A Level source.
• If you think you know basic information about the topic and want to explore more, pick a B Level source.
• If you want to go deeper into the topic, pick a C Level source.