Final answer:
Political borders are man-made, often influenced by natural geographic features and culture, but are not easily changed.
Step-by-step explanation:
The characteristic of political borders that is most accurate is that they are man-made. While natural physical geographic features such as mountains, rivers, and large lakes often influence where political boundaries of formal regions are set, the actual determination of these borders is a human construct. Features such as the Rio Grande between the United States and Mexico, and the Great Lakes between Canada and the United States, serve as natural demarcations but the precise borders are ultimately decided through treaties and negotiations. Political borders can also be influenced by culture, as seen in Eastern Europe where political borders often resemble ethnic boundaries. However, political borders are not easily changed as they are typically established through legal or diplomatic agreements and changing them usually requires substantial negotiation or conflict.