What six elements are most prevalent in living organisms?
Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus and Sulfur.
Most(I would say all of them, but may have some exceptions) of the living beings have proteins. A protein is a polymer(large chain) of amino acids of many tipes.
An amino acid is an organic molecule made by Carbon, Hydrogen, Oxygen and Nitrogen. The phosphorus is present in the DNA of each living being and in the energy molecules, ADP and ATP. About the Sulfur, I do not know much, but it is present in some amino acids and enzymes very important.