Which type of weathering is most associated with plant roots causing rocks to crack and break?

• A. Chemical Weathering
• B. Mechanical Weathering
• C. Physical Weathering
• D. Biological Weathering

Answer: (D)

Biological weathering is when living organisms contribute to breaking down rocks. Plant roots grow into tiny cracks and as they expand, they push outward and pry the rock apart. This physical disruption is driven by a living organism, so it’s classified as biological weathering. It differs from chemical weathering, where minerals are altered by chemical reactions, and from general mechanical weathering, which doesn’t involve living organisms. Over time, root wedging not only cracks rocks but also creates openings for water and other processes to deepen the weathering. So plant-root growth causing rocks to crack and break is a classic example of biological weathering.