Fill in the blanks with appropriate words : (a) ____ slopes aggravate weathering. (b) Erosion involves ____ of weathered materials. (c) Weathering are ot two maintypes _____ weathering and _____ weathering. (d) Hydration is a process in which _____ combines with a mineral. (e) The layer of loose rock material over the primary rock bed produced due to weathering is called _____.