(a) : Minor element are those which are required in quantity of less than milligram\/gram of dry matter but they are essential for proper growth and development of an organism e.g.,Cl,Mn,B,Zn,Cu Mo etc. These elements work as non-protein cofactor in enzymes e.g.,Zn,Cu etc. They also take part in oxidation reduction reactions e.g.,Cu, with variable valency. Chloride ion enhances activity of salivary amylase. Zinc is required for activity of carbonic anhydrase and alcohol dehydrogenase, etc.