Q. Which of the following is not non-essential element for plants :
(a) Potassium
(b) Sodium
(c) Aluminium
(d) Cobalt
Solution :
Correct option : A Non – essential elements are those mineral elements which are not required by the plants for their growth or they are needed in very minute quantities. They do not affect the overall growth and development of plants. Sodium, aluminium and cobalt are the non- essential elements required for metabolic activities in some plants. But Potassium is an essential element. It is a macronutrient that carries out several functions in the plants. Hence, it is not non- essential element. Thus, the correct answer is option A.
