Correct Response: D. The cyclical freezing and thawing of water that has seeped into fractures in rock outcrops is known as frost wedging. This process is a major agent of physical weathering in the northeastern United States and other cold climates. As the water in these fractures freezes, it expands and increases the size of the fracture, eventually helping break the rock apart over many years. Tectonic movements (A), such as earthquakes, are relatively rare in the northeastern United States and thus contribute little to rock weathering in that region. Precipitation (B) in the form of acid rain and oxidation of minerals in rocks (C) may result in chemical, but not physical, weathering of rocks.
