It's a bit of a trick question! Green mountains are called mountains because of their shape and elevation, not their color.

Here's why:

* Shape: Mountains are characterized by their steep slopes, peaks, and valleys. They are significantly higher than the surrounding land.

* Elevation: Mountains are defined as landforms rising at least 2,000 feet above sea level.

The color "green" just refers to the vegetation that typically covers mountains. This vegetation can vary depending on the climate and location, but green is common due to the abundance of trees and grass.

So, while the color might be what you notice first, the true defining features of a mountain are its shape and elevation.