1. River-valley civilizations developed in Sumer, Egypt, China, and the Indus River Valley. 2. After you have completed your outline, use the outline to write a 3-paragraph essay comparing two of the river valley civilizations: Mesopotamia, Egypt, the Indus River Valley, and the Yellow River Valley/China. 3. The first paragraph should be your introduction. The second paragraph should be a paragraph about the similarities between the two civilization. Finally, the third paragraph should be a paragraph describing the differences between the two civilizations.