Magnesium is a macro nutrient. Micro nutrients are essential elements that are needed by plants in small amount. They include $Fe,\, Cu,\, B,\, Mo,\, Mn,\,Cl,$ and $Ni$. Macro nutrients, on the other hand, are those essential elements that are required by plants in larger amount. The examples include $C,\,H,\, O,\, N,\,S,\, P,\,K,\, Ca$ and $Mg$.
The naturally occurring inorganic nutrient found in the soil and food that is necessary for the proper functioning of animal and plant bodies is defined as nutrition. Minerals are vital elements essential for the body.