Which type of weathering involves the growth of plants that alter rocks?

Biological weathering occurs when living organisms, such as plants, interact with rocks and minerals, leading to the alteration of these materials. The roots of plants can grow into cracks in rocks and exert pressure, which can cause the rock to break apart. Additionally, the organic acids produced by plant roots can chemically react with minerals in the rocks, further enhancing the weathering process. This type of weathering is crucial in soil formation and can significantly impact the landscape over time.

In contrast, physical weathering includes processes such as freeze-thaw cycles and abrasion that break down rocks without altering their chemical composition. Chemical weathering involves the alteration of the chemical structure of minerals due to reactions, often with water or acids, but does not specifically involve biological agents. Thermal weathering, which results from temperature changes causing expansion and contraction in rocks, also operates independently of biological influences. Thus, biological weathering is the correct choice as it directly ties the process of weathering to the growth and activity of plants.