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.

At deep-ocean trenches, you’ll find a dramatic display of geology in action where denser oceanic plates slide beneath lighter continental plates in a process known as subduction. This event not only shapes the ocean floor but also triggers volcanic activity and earthquakes, reminding us of Earth’s dynamic nature! These areas are fascinating for scientists studying plate tectonics, as they're hotbeds for various geological phenomena. By analyzing the different strata and materials that come to the surface, researchers can uncover crucial information about Earth’s history and potentially predict seismic activity, ultimately aiding in disaster preparedness.