Minute quantities of chemicals are called minerals, vital for the smooth running of the body. Role – salt (maintains electrical balance, source- common salt or milk), calcium (necessary for ossification of bone, formation of teeth, source- milk or cream), iron (composition of hemoglobin, source-meat or eggs), iodine (deficiency leads to goiter, source- sea foods or iodized salt), fluorine (prevents dental decay, source- water or sea fish).