Final answer:
The Rio Grande, Sabine, and Red River are examples of physical features that create political borders.
Step-by-step explanation:
The Rio Grande, Sabine, and Red River are examples of physical features that create political borders. Many political boundaries are natural features such as rivers, mountain ranges, and large lakes. For example, the Rio Grande forms part of the border between the United States and Mexico. These geographic features serve as convenient formal borders, but they can also lead to political disputes if valuable resources are involved.