You see mountains and ocean basins on the Earth's crust, which is the outermost layer of the Earth.

Here's why:

* Crust: This is the thin, rocky outer layer of the Earth. It's divided into two types:

* Continental crust: Forms the continents and is thicker and less dense.

* Oceanic crust: Forms the ocean floor and is thinner and denser.

* Mountains: Form when tectonic plates collide and push up the crust.

* Ocean Basins: Form when tectonic plates move apart, creating space for new crust to form.

While you see the effects on the crust, remember that the processes that create mountains and ocean basins are driven by movements within the Earth's mantle, the layer beneath the crust.