Definition: Gravel is an environmental material which is composed of pieces of rock that are at least two millimeters (2mm) in its largest dimension and no more than 75 millimeters.
Definition: A tract of crop or grazing land, as well as the group of buildings with and often surrounding a farmhouse, including barns, sheds, and other outbuildings, used for agricultural production.
Definition: A habitat that is in or on a body of water containing low concentrations of dissolved salts and other total dissolved solids (<0.5 grams dissolved salts per litre).
