Abandoned Wells: a hazard because wells left on vacated lands can channel water contaminated by pesticides and fertilizer straight down into the water table. Abrasion: the wearing away of rock surfaces by small particles moved by air or water.
Animals are multicellular and possess mitochondria, a complex nervous system, and cells protected by a membrane and filled with complex organelles.
Adaptation: how living things change what they do or what they are to survive in a particular environment.
In this the organism is not a passive recipient of external circumstances; the relationship is interactive. Aggradation: a downward accumulation of stream-carried inorganic matter.
Angle of Repose: the steepest angle that slope, rock, or detritus material settles into without toppling.
Builders of flood-prone roads and sliding hillside homes in California ignore the angle of repose so often that it could be renamed the angle of depose.