Death due to disease is called death by natural causes. There are four main types of disease: pathogenic disease, deficiency disease, hereditary disease, and physiological disease. Diseases can also be classified as communicable and non-communicable disease.
A watershed is the area of land where all of the water that falls in it and drains off of it goes to a common outlet.
The Chesapeake Bay Watershed. A watershed is an area of land that drains to a particular river, lake, bay or other body of water. Watersheds are sometimes called âbasinsâ or drainage basins.. We all live in a watershed. Some watersheds, like that of your local stream or creek, are small. Others, like the Chesapeake Bay watershed, are very large.