The processes of mechanical weathering transform rocks exposed at the surfaceover time. In frost wedging, seasonal freezing of water causes expansion of cracks in rock. Salt crystal growth within fissures or cracks in rock similarly causes expansion and mechanical weathering. Sheeting occurs when large sheets of rock dome upward and peel off when overlying rocks are eroded away, decreasing pressure. Biological activity can also cause mechanical weathering ofrocks when living things such as the roots of plants or bacteria cause rocks to break apart. Fill in the sentences below to explore the four different mechanical weathering processes. Climatehas a crucial influence on the rates of all types of mechanical weathering.Salt crystal growthcan contribute to crumbing roadways in areas where saltis spread to melt ice and snow in winter. The fissures formed as a result of Sheetingin exfoliation domes can be further enlarged by Frost wedgingin areas subjected to seasonal freeze-thaw cycles. The break down of rock by moving fresh materials to the surface by burrowing animals is an example of mechanical weathering due to Biologicalactivity.