Polyps are a common finding during recommended screening exams of the colon and rectum, occurring in approximately 20 to 30% of American adults. Polyps are abnormal growths arising from the inner lining of the colon or rectum. Some polyps are flat; others have a stalk. Polyps can occur throughout the large intestine, but are more commonly found in the left colon, sigmoid colon and rectum. The large majority of polyps will not become cancers; however, certain types of polyps are precursors to cancer development.
DEFINITION of 'Nonrenewable Resource'. A resource of economic value that cannot be readily replaced by natural means on a level equal to its consumption. Most fossil fuels, such as oil, natural gas and coal are considered nonrenewable resources in that their use is not sustainable because their formation takes billions of years.
At present, the main energy source used by humans is non-renewable fossil fuels. Since the dawn of internal combustion engine technologies in the 17th century, petroleum and other fossil fuels have remained in continual demand.oal, produced over millions of years, is a finite and non-renewable resource on a human time scale. A non-renewable resource (also called a finite resource) is a resource that does not renew itself at a sufficient rate for sustainable economic extraction in meaningful human time-frames.