Correct Option
The correct option is (a).
Explanation
Sea waves act as active agents of erosion and deposition along coastal regions. The erosional work of sea waves creates distinct landforms through a sequential process involving the widening of cracks, the formation of cavities, and the eventual collapse of rock structures.
Statement-wise Analysis
- Statement 1 is Correct: Sea waves continuously strike against coastal rocks, causing cracks to develop. Over time, these cracks become larger and wider due to hydraulic action and abrasion. This leads to the formation of hollow, cave-like depressions on the rocks known as sea caves.
- Statement 2 is Incorrect: As the cavities of sea caves enlarge, eventually only the roof of the cave remains, bridging the gap. This feature is known as a sea arch. A stack is formed at a later stage of erosion.
- Statement 3 is Incorrect: Continued erosion eventually breaks the roof of the sea arch. When the roof collapses, isolated wall-like features are left standing in the sea. These vertical rock columns are called stacks, not sea arches.
Key Takeaway: The evolution of coastal erosional landforms follows a specific sequence: Cracks → Sea Caves → Sea Arches → Stacks.