Plate tectonics is A. the slow lateral movement of segments of the Earth's hard, outermost shell as a result of conduction currents deep inside the Earth.
(Plate tectonics; is; A. the slow lateral movement of segments of the Earth's hard, outermost shell as a result of conduction currents deep inside the Earth)
Plate tectonics
is
A. the slow lateral movement of segments of the Earth's hard, outermost shell as a result of conduction currents deep inside the Earth