What term describes the mechanism by which convection currents in the mantle move the lithosphere like a conveyor belt?

• A. Basal Drag
• B. Slab Pull
• C. Mantle Convection
• D. Normal Polarity

Answer: (A)

Convection in the mantle pushes and drags against the base of the tectonic plates. The friction and coupling at the lithosphere's base transmit the mantle’s flow to the surface, so the plates move along like a conveyor belt. This specific transfer of motion from mantle flow to the lithosphere is called basal drag.

Other ideas describe different aspects: slab pull is the effect of a sinking subducting slab pulling a plate, mantle convection is the overall circulation in the mantle rather than the surface-driving mechanism, and normal polarity is about magnetic orientation, not plate motion.