Which term describes the process of forming new oceanic crust at divergent plate boundaries?

Which term describes the process of forming new oceanic crust at divergent plate boundaries?

• A. Rift Valley
• B. Sial
• C. Sewage
• D. Sea-floor Spreading

Answer: (D)

The main idea tested is how new oceanic crust is created at divergent plate boundaries. When two tectonic plates pull apart at mid-ocean ridges, mantle material rises, melts, and magma erupts to fill the gap. As this magma cools, it forms fresh oceanic crust, mainly basalt, pushing the plates apart and expanding the ocean floor. The youngest rocks are right at the ridge, becoming older as you move away, and the pattern of magnetic stripes in the crust provides evidence of this spreading. The other terms don’t describe this process: a rift valley is a surface feature on continents, sial refers to continental crust composition, and sewage is unrelated.

The main idea tested is how new oceanic crust is created at divergent plate boundaries. When two tectonic plates pull apart at mid-ocean ridges, mantle material rises, melts, and magma erupts to fill the gap. As this magma cools, it forms fresh oceanic crust, mainly basalt, pushing the plates apart and expanding the ocean floor. The youngest rocks are right at the ridge, becoming older as you move away, and the pattern of magnetic stripes in the crust provides evidence of this spreading. The other terms don’t describe this process: a rift valley is a surface feature on continents, sial refers to continental crust composition, and sewage is unrelated.