What feature forms a long underwater mountain range?

• A. Abyssal plain
• B. Continental shelf
• C. Mid-ocean ridge
• D. Trench

Answer: (C)

Forming a long underwater mountain range comes from seafloor spreading at divergent plate boundaries. As tectonic plates move apart, magma rises, cools, and creates new oceanic crust. This continuous process builds a continuous chain of underwater mountains that winds around the globe—the mid-ocean ridge. It stays elevated above the surrounding deep sea floor because the young, hot crust is more buoyant and the crest often features a rift valley.

Abyssal plains are flat regions of the deep ocean floor, continental shelves are the submerged edges of continents, and trenches are deep, narrow depressions where one plate subducts under another. That’s why this description points to the mid-ocean ridge.