(a) Calcium: Calcium is essential for the formation of healthy bones and strong teeth.
(b) Sodium: Sodium is essential for the proper functioning of the nervous system.
(c) Potassium: Potassium is essential for normal growth and also to keep cells and blood healthy.
(d) Iron: Iron is an important part of haemoglobin, which is the substance in red blood cells that carries oxygen to all the cells of the body.