Which statement best describes a Sea Cave?

• A. A cave formed by wave erosion in a coastal cliff.
• B. A tidal pool in a rocky shoreline.
• C. A hollowed rock formed by river erosion inland.
• D. A shallow underwater trench.

Answer: (A)

Sea caves are formed when the energy of ocean waves erodes weaknesses in a coastal cliff, such as cracks and joints. Repeated pounding by waves uses hydraulic action (water and air being forced into cracks) and abrasion (rock fragments grinding away at the rock) to widen a hollow at the base of the cliff. Over time this process creates a cavity opening into the rock—a sea cave. That’s why the statement describing a cave formed by wave erosion in a coastal cliff is the best fit. The other options describe different features: a tidal pool is a water-filled depression along the shore, inland river erosion would produce features like valleys or gorges, and a shallow underwater trench is a seabed feature not a coastal cave.