Which feature forms the backbone of coastal defense against storm surge along the shore?

• A. Dunes
• B. Barrier Flat
• C. High Salt Marsh
• D. Peat Deposits

Answer: (A)

Dunes form the primary physical barrier at the shore, so they are the main line of defense against storm surge. The raised ridge of sand acts like a wall that slows and breaks incoming waves and surge, reducing the energy that reaches inland. Vegetation such as grasses roots stabilizes the sand, helping the dune hold its height and shape during high winds and floodwaters, so it remains effective as long as it isn’t breached. Barrier flats and salt marshes behind the dunes do provide additional protection by absorbing some energy and trapping sediment, but they rely on an intact dune system in front of them to be most effective. Peat deposits don’t form a strong, standing barrier against surge. So the dune system’s height, stability, and energy-dissipating function make it the backbone of coastal defense.