Here's why:

* Reddish ball: Mars is known for its distinctive rusty red color due to iron oxide (rust) on its surface.

* Permanent dark regions: These are large, dark areas on Mars known as albedo features. They are not oceans or seas, but rather vast plains and lowlands that appear darker than the surrounding reddish terrain.

* Change in intensity: The intensity of these dark regions can vary slightly due to dust storms that can engulf the planet and obscure the features, or seasonal changes in the amount of ice and frost covering the surface.

Let me know if you'd like to learn more about Mars!