Which term best describes the erosional process driven by the pressure of water and trapped air in cracks?

Which term best describes the erosional process driven by the pressure of water and trapped air in cracks?

• A. Groynes
• B. Housing tenure
• C. Hydraulic action
• D. Greenfield site

Answer: (C)

Hydraulic action is the erosional process at work when water pressure and trapped air push against cracks in rock. When a wave crashes, air and water are forced into any joints or fissures. The pressure from the water, plus the sudden release when the wave retreats, works like a wedge, widening those cracks and causing pieces of rock to break off over time. This physical grinding and breaking is a primary way that cliffs are worn away on coastlines, helping to create features like caves and arches. The other terms aren’t describing this process: groynes are man-made structures that interrupt longshore drift, housing tenure is about who owns or rents homes, and a greenfield site is undeveloped land considered in planning.

Hydraulic action is the erosional process at work when water pressure and trapped air push against cracks in rock. When a wave crashes, air and water are forced into any joints or fissures. The pressure from the water, plus the sudden release when the wave retreats, works like a wedge, widening those cracks and causing pieces of rock to break off over time. This physical grinding and breaking is a primary way that cliffs are worn away on coastlines, helping to create features like caves and arches.

The other terms aren’t describing this process: groynes are man-made structures that interrupt longshore drift, housing tenure is about who owns or rents homes, and a greenfield site is undeveloped land considered in planning.