Which crust underlies the ocean?

• A. Continental crust
• B. Lithosphere
• C. Oceanic crust
• D. Core

Answer: (C)

Under the oceans lies the oceanic crust, a relatively thin but dense shell that forms the seafloor. It’s mainly basalt and gabbro and sits atop the mantle as part of the rigid outer shell of the planet. Continental crust underlies the continents and is thicker and less dense, composed largely of granitic rocks. The lithosphere is the overall rigid outer layer that includes both oceanic and continental crust plus the upper mantle; it’s not a single crust under the ocean. The core sits far deeper inside Earth. So the crust beneath the ocean is oceanic crust.