An upwelling convection current can be linked with which surface effect?

Correct answer: Surface spreading

When a convection current rises, it carries hot mantle material upward toward the surface. At a suitable boundary, this upward movement can help push or spread material apart, producing surface spreading. In plate-tectonic explanations, upwelling beneath a divergent boundary is associated with the creation and outward movement of new oceanic crust. Therefore, option A, surface spreading, is correct.

The answer follows the direction of movement: upwelling brings material toward the surface, and horizontal movement away from the rising zone can spread it. Surface freezing is not the general effect being described, while a river flood and forest growth are unrelated surface processes. The question uses a simplified school-level link, so it does not claim that every upward current automatically causes spreading; it identifies the surface effect commonly associated with upwelling in tectonic settings. Hence option A is the best choice.