Which coastline faces a spreading center and has varied topography?

• A. Collision coasts
• B. Marginal sea coasts
• C. Open coastlines
• D. Trailing-edge coasts

Answer: (D)

Facing a spreading center means the coastline sits on the trailing edge of a tectonic plate where the crust is being pulled apart. At these divergent boundaries, the crust often experiences extension, faulting, and uneven subsidence or uplift. That tectonic stretching, combined with river sediments piling up into deltas and terraces, creates a coast with a mix of features and a varied, nonuniform topography. In contrast, coasts near subduction zones (collision or leading-edge coasts) tend to be shaped by compression and mountain-building, producing more rugged and high-relief shorelines, while marginal sea or open coastlines aren’t specifically defined by proximity to a spreading center. So the coastline that faces a spreading center naturally develops varied topography, classifying it as the trailing-edge coast.