Here's why:

* Compression: This refers to the pushing together of Earth's crustal plates.

* Folding: When immense pressure is applied to rock layers, they bend and fold instead of breaking. This creates the characteristic wave-like structures of fold mountains.

Examples of Fold Mountains:

* The Himalayas

* The Alps

* The Andes

* The Appalachian Mountains

Let me know if you'd like to know more about fold mountains!