The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen, though other elements are found in the side-chains of certain amino acids. About 500 amino acids are known and can be classified in many ways.
Friendly is a town in Tyler County, West Virginia, in the United States.
This down-home, growing, outdoorsy community about 30 miles west of Vail features friendly folks and a cozy mountain setting where residents and visitors love to challenge themselves on some of nature's finest playgrounds.