Which process helps in the decomposition of rocks?

• A. Mechanical wearing
• B. Chemical weathering
• C. Physical erosion
• D. Structural alteration

Answer: (B)

The process that helps in the decomposition of rocks is chemical weathering. This process involves the alteration of minerals within the rocks through chemical reactions, often facilitated by water, air, or biological activity. For example, acidic rainwater can react with minerals like feldspar in granite, resulting in the formation of clay minerals and soluble ions. This transformation not only breaks down the structure of the rock but also contributes to soil formation and nutrient cycling.

Different processes like mechanical wearing and physical erosion primarily focus on the physical breakdown of rocks into smaller fragments without changing their chemical composition. Mechanical wearing involves the physical forces acting on rocks, such as freeze-thaw cycles or abrasion. Structural alteration typically refers to the changes in the rock's physical structure due to tectonic forces or extreme pressure and temperature, rather than its decomposition. Therefore, chemical weathering is distinctly characterized by its role in the chemical changes and decomposition of minerals, making it the correct choice.