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.
  Hardy County is a county located in the U.S. state of West Virginia. As of 2000, the population is 12,669. Its county seat is Moorefield.etersburg is an independent city. It is not located within any counties.