Choose two categories from the river valley civilizations sheet. then, write an essay comparing and contrasting the four civilizations in those two categories. for example, you could choose to compare and contrast the governments and the writing systems of the four civilizations.

In e. c. tolman's experiment, some rats were trained to run through mazes for standard food goals, while other rats were allowed to explore the mazes for 10 days without food goals or other rewards. later, when food rewards were placed in a box at the far end of the maze, the previously unrewarded rats reached the food box as quickly as the rewarded rats after only one or two trials. this experiment demonstrated that the rats had the ability to form of their surroundings.