Perhaps no factor is more useful in the control of disease than the science of sewage disposal. It safeguards a community’s water supply by removing water-carried wastes including microscopic dissolved material, solid matter such as human waste, and harmful chemicals and bacteria. Sewage is generally divided into two classes: domestic, or sanitary, sewage and industrial [...]

Competition in Communities Competition is a characteristic of all communities. Plant roots in dry range lands compete for water. The trees of a rain forest compete for light. Crops compete for both of these as well as for nutrients. Competition is usually keen in areas where one type of community seems to overlap another. For [...]

WATER CONSERVATION Polluted water in one part of the world affects water sources everywhere. This happens because water moves through what is called the hydro logic cycle. In the hydro logic cycle 1) water moves into the air and clouds as it evaporates from oceans, lakes, and rivers. 2) the winds that blow around the [...]