Repeated freezing and thawing in cold areas is an example of what?

Correct answer: Physical weathering

Direct answer: Option A, physical weathering. In cold regions, water enters cracks in rock. When it freezes, it expands and pushes the crack wider; when it thaws, more water can enter. Repeated freeze–thaw cycles eventually break the rock into pieces. This is mechanical action, so it is physical weathering, also called frost action or frost wedging. Option A is correct. Option B, carbonation, is chemical weathering in which carbonic acid in water reacts with minerals such as limestone. Option C, solution, is the chemical dissolving of soluble minerals in water. Option D, oxidation, is a chemical reaction commonly involving oxygen, such as rusting of iron-bearing minerals. Freezing and thawing may occur with chemical processes, but the described repeated expansion and cracking is physically mechanical. Memory cue: frost breaks; acids and oxygen chemically change.