Which statement best describes the theory of plate tectonics?

Plate tectonics theory basically states the earth is made up of constantly moving massive plates of rock.

Sections of Earth's continents are in a slow and constant movement

Explanation:

The earth's crust is comprised of many broken fragments which are commonly known as lithospheric plates. These are of two types namely, the continental crust and the oceanic crust.

These plates continuously move over the less dense layer of the asthenosphere, where the rocks tend to flow in response to deformation. This movement of continents is due to the creation of convection current in the mantle and this is possible because of the heat provided from the extreme internal layer of the earth. These plates move at a very slow rate ranging from millimeters to centimeters. Due to this continuous motion, the three types of tectonic boundaries are formed-

Divergent boundary Convergent boundary Transform boundary

This theory is known as the plate tectonic theory.