What happens at divergent plate boundaries?

• A. They create new crust at mid-ocean ridges
• B. They generate trenches
• C. They form volcanic arcs
• D. They produce subduction zones

Answer: (A)

Divergent boundaries are where plates move apart, allowing mantle material to rise into the gap. As this upwelling magma reaches the surface and cools, it forms new crust, especially along mid-ocean ridges where the sea floor spreads and grows outward. That continual creation of new crust from upwelling magma is the defining outcome of divergence, which is why creating new crust at mid-ocean ridges is the best description.

Trenches form where one plate sinks beneath another at convergent boundaries, not where plates pull apart. Volcanic arcs develop above subduction zones as melting occurs in the descending slab, and subduction zones are regions of crust destruction rather than creation. So those features reflect other boundary types, not divergent ones.