Principal Element-

These includes calcium, magnesium, sodium, potassium, phosphorous, sulphur and chlorine.
Out of these, Na, K and Cl2 are involved mainly in the maintainance of acid base balance and osmotic control of water metabolism; Ca, P, Mg are the constituents of bones and teeth; phosphorous is a constituent of body cells of soft tissue, such as muscles, liver etc. sulphur in cysteine and methionine, thiamine, biotin and CoA.