A Sea Island is best described as:

• A. A submerged coral atoll.
• B. A coastal island formed by sediment deposition close to shore.
• C. A man-made barrier.
• D. A freshwater island in a river.

Answer: (B)

Sea Islands are coastal islands formed by sediment deposition close to shore. They build up from sand carried by waves and longshore drift, creating narrow islands that run parallel to the coast and often sit behind a fringe of dunes or marsh. Over time, repeated wave overwash and vegetation help stabilize and raise these features, so they remain as natural, dynamic barriers that protect inland areas. This makes them distinct from submerged coral atolls, which are ring-shaped reefs around a lagoon, from man-made barriers, which are artificial structures, and from freshwater river islands, which form in inland waterways.