The correct option is 2 only
Explanation
In regions with soluble rocks like limestone or dolomite, the action of groundwater through chemical dissolution creates distinct landforms known as Karst topography. Caves are prominent erosional features in such landscapes.
- Statement 1 is Incorrect: Caves typically form in areas where there are alternating beds of rocks (such as shales, sandstones, or quartzites) with limestones, or in regions where limestones are dense, massive, and occur as thick beds. The dissolution process creates voids within these rock layers.
- Statement 2 is Correct: Water does not move only vertically. It percolates down through cracks and joints (vertical movement) and also moves horizontally along bedding planes. It is primarily along these horizontal bedding planes that limestone dissolves to form long, narrow gaps, which eventually expand into caves.
- Statement 3 is Incorrect: A cave that has openings at both ends is technically referred to as a tunnel. Sinkholes are funnel-shaped depressions on the surface formed by the dissolution of limestone or the collapse of a cave roof, not the cave structure itself.
Key Takeaway: Caves in Karst regions are formed by the dissolution of limestone by groundwater moving both vertically through joints and horizontally along bedding planes. A cave with two openings is called a tunnel.