Weathering is the most likely cause of a rock cracking and crumbling. Weathering is the process of breaking down rocks, minerals, and soils at the Earth's surface. It is caused by the combined action of physical, chemical, and biological processes. Physical weathering includes the action of wind, water, ice, and temperature changes. Chemical weathering includes the action of acids, bases, and other chemicals in water, air, and soil. Biological weathering includes the action of plants, animals, and microorganisms.