Region where plates are moving apart and new ocean or rift valley forms; spreading center forms the junction.

• A. Core
• B. Density
• C. Divergent Plate Boundary
• D. Crust

Answer: (C)

Moving apart plates define a divergent plate boundary. At this boundary, the spreading center is where magma rises and new oceanic crust is created as the plates separate. If continental crust is involved, divergence forms a rift valley that can develop into an ocean basin. This description—plates pulling apart, creation of new crust at the spreading center—fits divergent plate boundaries best. The other terms refer to Earth’s internal layer (core), a property (density), or a different outer layer (crust) and do not describe the boundary interaction that produces upwelling magma and new crust.