The oceanic plates sinking under a continental plates are evident when we pull up a location like the Andes mountains. This shows how deep earthquakes are happening. And looking at the earthquakes happening near Mt. Everest is helpful too--those earthquakes are only shallow (two continental plates colliding).
This means we went back to the Driving Question Board to see what we could answer based on what we've figured out! Goodness we've figured a lot out!