When two plates made of continental lithosphere collide, they form mountain ranges. Here's why:

* Continental lithosphere is less dense than oceanic lithosphere. This means it doesn't subduct (sink) under the other plate.

* Collision creates immense pressure. The two plates buckle, fold, and uplift, creating mountains.

* Examples: The Himalayas (formed by the collision of the Indian and Eurasian plates) and the Appalachian Mountains (formed by the collision of North America and Africa) are classic examples of mountain ranges formed by continental-continental collisions.

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