Here's why:
* Transform boundaries are where two tectonic plates slide horizontally past each other.
* No new crust is created because the plates are not pulling apart (like in a divergent boundary).
* No crust is destroyed because the plates are not colliding (like in a convergent boundary).
The most famous example of a transform boundary is the San Andreas Fault in California, where the Pacific Plate is sliding past the North American Plate.
