Question

The theory proposing that oceanic ridges are formed by currents of deep-seated magma rising up from the mantle (often during volcanic eruptions), creating a new crust on the ridges is known as

weathering

plate tectonics

continental-continental movement

volcanism

Answer 1

Ans- B, plate tectonics

The theory plate tectonics tells how the plates move relative to one another. At the divergent plate boundary, the plates move away from each other forming rifts over continents and ridges over ocean. At convergent plate boundary, the plates come towards one another and subduction zone or collision occurs. At transform plate boundary two plates only slide pass each other.

Convection cells in asthenosphere form this plate tectonic activity.