Sagot :
Upwelling currents in the molten material beneath the crust.
The rocks that make up the crust are light, compared with the metal-rich material beneath. The crust floats on top like an iceberg. Slow-moving currents underneath propel the continents around the surface
The rocks that make up the crust are light, compared with the metal-rich material beneath. The crust floats on top like an iceberg. Slow-moving currents underneath propel the continents around the surface