Question

which of the following is the best explanation for what caused the cracks in the rock pictured here?
mechanical weathering due to frost wedging
erosion due to frost wedging
chemical weathering due to frost wedging
chemical weathering due to a reaction with water

Explanation:

Frost wedging is a form of mechanical weathering. In this process, water seeps into cracks in rocks. When the temperature drops and the water freezes, it expands (since water expands when it freezes). This expansion exerts pressure on the rock walls of the cracks, gradually widening and deepening the cracks over time. Mechanical weathering involves physical processes that break rocks into smaller pieces without changing their chemical composition. Erosion is the process of transporting weathered material, which is not what is causing the cracks here. Chemical weathering involves a change in the rock's chemical composition, which frost - wedging does not.

Answer:

Mechanical weathering due to frost wedging