The theory of plate tectonics explains many geological events, including earthquakes, volcanoes, and mountain building. According to the theory of plate
tectonics, which of the following is true?

A. Earth is composed of four layers: the crust, mantle, outer core and inner core.

B. The rocks found on Earth have been changed by natural forces that occur on the
planet.

C. Earth's hard crust is broken into large plates, which keep the continents in fixed
locations.

D. Earth's hard outer shell is broken into large, rigid plates that float atop the
asthenosphere