Weathering is the process by which rock materials are broken down by the action of physical or chemical processes.
Mechanical weathering is the breakdown of rock into smaller pieces by phisical means.
Abrasion is the grinding and wearing away of rock surfaces through the mechanical action of other rock or sand particles. Wind also causes abrasion.
Plants can also wedge between rocks and tear them appart.
Animals believe it or not are also things that can cause weathering by burrowing into the soil and move soil particles around and mess up the ground and the animals that do this are........Moles, ants, rabbits, spiders,worms and even foxes.
Chemical weathering is also a problem especialy acid rain.Chemical weathering is the wearing away at rocks and minerals by erosion.