A "Mystery" in Our Understanding of Plate Tectonics Has Been

Multiple Choice

A "mystery" in our understanding of plate tectonics has been, until recently, the nature of the power source capable of moving the plates and the continents embedded within them. Recent evidence indicates the power source to be:

A) the readjustment of the surface to continual shrinking of the whole Earth.
B) convection currents within the Earth's mantle is moving the plates.
C) the action of ocean currents is dragging along the seafloor, causing the seafloor and the continents to move.
D) the continual vibration from earthquakes and volcanoes slowly moves the continents equatorward under the influence of centrifugal force.