Posted by ROSHAN B.S on Aug. 24, 2014, 5:17 p.m.
Calcium is the chemical element with symbol Ca and atomic number 20. Calcium is a soft ay alkaline earth metal, and is the fifth-most-abundant element by mass in theEarth's crust. Calcium is also the fifth-most-abundant dissolved ion in seawater by bothmolarity and mass, after sodium, chloride, magnesium, and sulfate.[2]
Calcium is essential for living organisms, in particular in cell physiology, where movement of the calcium ion Ca2+ into and out of the cytoplasm functions as a signal for many cellular processes. As a major material used in mineralization of bone, teeth andshells, calcium is the most abundant metal by mass in many animals.