Write an essay comparing and contrasting the early river valley civilizations that developed in mesopotamia, egypt, the indus river valley, and china. step 1. write the introduction (includes the thesis statement). step 2. write the body of the essay (compare the four early river-valley civilization). step 3 contrast the four early river valley civilizations). step 4 conclusion that summarizes the major ideas and restates the thesis. write no more than three of four sentences.