What are the four major elements and their source on which the body relies for form and function?

There are many different elements that form a part of the chemistry of the body, but there are four which predominate, which are carbon, hydrogen, oxygen, and nitrogen (sometimes known collectively as CHON). All of these elements are readily available in the environment. Water is composed of oxygen and hydrogen, the air is 70% nitrogen, and carbon is obtained from carbon dioxide which is also in the air. Various plants and bacteria can use these simple compounds and elements to build more complex organic compounds, and these complex compounds work their way up the food chain to us.