Answer: Phosphorus
Calcium is required for muscle contraction, iron is needed for the synthesis of haemoglobin, while sodium regulates acid-base equilibrium.
Phosphorus
Phosphorus is involved in the energy transfer process, including the creation of sugar and alcohol esters and the production of adenosine triphosphate (ATP). In addition to these roles, phosphorus plays a regulatory role in many enzymatic processes, where inorganic phosphorus regulates reaction rate.
