Question

which statement describes one event that happens at deep-ocean trenches?
○ crust is formed.
○ mountains are formed.
○ seafloor spreading occurs.
○ denser plates slide under lighter plates.

Explanation:

Deep-ocean trenches form at subduction zones, where denser oceanic tectonic plates slide beneath less dense (lighter) plates. Crust formation and seafloor spreading occur at mid-ocean ridges, not trenches. Mountain formation typically happens at convergent boundaries between continental plates, not at deep-ocean trenches.

Answer:

D. Denser plates slide under lighter plates.