Describe essential minerals on the basis of their diverse functions.

(N/A) Essential elements can be grouped into four broad categories based on their diverse functions:
$(A)$ Essential elements as components of biomolecules and hence structural elements of cells,e.g.,carbon,hydrogen,oxygen,and nitrogen.
$(B)$ Essential elements that are components of energy-related chemical compounds in plants,e.g.,magnesium in chlorophyll and phosphorus in $ATP$.
$(C)$ Essential elements that activate or inhibit enzymes. For example,$Mg^{2+}$ is an activator for both ribulose bisphosphate carboxylase-oxygenase $(RuBisCO)$ and phosphoenol pyruvate carboxylase ($PEP$ carboxylase). $Zn^{2+}$ activates alcohol dehydrogenase. $Mo$ activates nitrogenase during nitrogen metabolism.
$(D)$ Essential elements that can alter the osmotic potential of a cell,such as potassium $(K^+)$,which plays an important role in the opening and closing of stomata.