Which statement about oceanic crust is true?

• A. It is less dense than continental crust
• B. It is found on land
• C. It is found underneath the oceans, is denser than continental crust, and can be subducted
• D. It cannot be subducted

Answer: (C)

The main idea is that oceanic crust is found beneath the oceans and is denser than continental crust, which allows it to sink back into the mantle at plate boundaries. Oceanic crust forms at mid-ocean ridges, is relatively thin, and is made mostly of basalt. Because it is denser, when it converges with less dense continental crust (or with another oceanic plate), it tends to subduct, creating trenches and volcanic activity. This is why the statement that oceanic crust lies under the oceans, is denser than continental crust, and can be subducted is true. It is not found on land, and its ability to be subducted is a key feature of how plate tectonics shapes the oceans.