Rocks are worn away through a process called weathering, which can be divided into mechanical, chemical, and biological weathering. Mechanical weathering occurs when physical forces break rocks into smaller pieces without altering their chemical composition. Chemical weathering involves the alteration of minerals through chemical reactions, often caused by water, acid, and oxygen. Biological weathering is driven by living organisms such as plants and fungi that can break down rocks. Erosion then transports these weathered materials through wind, water, or ice, leading to landscape changes over time. Together, these processes contribute to the continual cycle of rock formation and alteration in the Earth's crust.