Convergent Boundaries:

* Subduction Zones: One tectonic plate slides beneath another. The denser plate (usually oceanic) sinks into the mantle, where it melts. This process, called subduction, destroys the oceanic crust.

* Continental Collisions: When two continental plates collide, neither is dense enough to subduct. Instead, they buckle and fold, creating mountain ranges. Some crust might be scraped off and deformed, but it's not entirely destroyed.

Divergent Boundaries:

* Mid-Ocean Ridges: These are underwater mountain ranges where new oceanic crust is created. Magma rises from the mantle and erupts, solidifying into new crust. This process, called seafloor spreading, pushes the plates apart.

* Continental Rifts: These are areas where the continental crust is being pulled apart. As the plates separate, magma rises and can erupt, eventually forming new oceanic crust.

In Summary:

* Convergent boundaries: Destroying crust

* Divergent boundaries: Creating crust

Let me know if you'd like more details about any of these processes!