Question

which processes relate to mechanical weathering? check all that apply. freezing and thawing plant growth oxidation abrasion acid rain

Explanation:

• Freezing and thawing: Water expands when it freezes. If water gets into cracks in rocks and then freezes, it can widen the cracks. This is a physical (mechanical) process as it breaks rocks without changing their chemical composition.
• Plant growth: As plant roots grow into cracks in rocks, they exert pressure. Over time, this pressure can break the rocks apart. It is a mechanical process since it is based on physical force rather than chemical change.
• Abrasion: This is when rocks are scraped or rubbed against each other (e.g., by wind - blown sand, water - carried pebbles). The physical rubbing breaks the rocks into smaller pieces without altering their chemical makeup.
• Oxidation: This is a chemical process. For example, when iron in rocks reacts with oxygen (in the presence of water) to form iron oxides (rust), the chemical composition of the rock (or the iron - containing minerals in it) changes.
• Acid rain: Acid rain (which contains acids like sulfuric acid from pollutants reacting with water in the atmosphere) can react with minerals in rocks (e.g., calcium carbonate in limestone). This is a chemical reaction that changes the chemical composition of the rock.

Answer:

freezing and thawing, plant growth, abrasion