Glossary of Terms. Bronchus / Bronchi / Bronchioles. The airways of the lungs. When a person takes in a breath of air, the air travels through the nose or mouth, into the larynx, then into the trachea, which is the main passageway into the lungs. The trachea divides into a right and left main bronchus.
Plant and animal life, atmosphere and water are the major causes of weathering. Weathering breaks down and loosens the surface minerals of rock so they can be transported away by agents of erosion such as water, wind and ice. There are two types of weathering: mechanical and chemical.
Weathering is the breaking up of surfaces by forces such as the air and water of the atmosphere. Weathering processes cause the breakup of rock materials in the Earth's uppermost layer. Some of these processes are mechanical, for example the expansion and contraction caused by sudden, large changes in temperature, the expansive force of water freezing in cracks, the splitting caused by plant roots, and the impact of running water.