Identify the set of micronutrients (nutrients required by plants in small…

Plant nutrients are classified by how much of them a plant needs. Macronutrients — such as Nitrogen, Phosphorus, Potassium, Calcium, Magnesium, and Sulphur — are required in comparatively large amounts, whereas micronutrients are trace elements needed only in very small quantities, yet they remain essential for processes such as chlorophyll formation and enzyme activation. The standard set of plant micronutrients includes Zinc, Iron, Manganese, Copper, Boron, Molybdenum, Chlorine, and Nickel.

Testing each given set against this classification, the set Zinc, Iron, Manganese is made up entirely of micronutrients — each of these three elements is a trace element needed by plants in minute quantities, exactly matching the description in the question.

• Potassium, Magnesium, Copper mixes two macronutrients — Potassium and Magnesium — with only one micronutrient, Copper, so it is not a pure micronutrient set.

• Copper, Phosphorus, Calcium pairs one micronutrient, Copper, with two macronutrients, Phosphorus and Calcium.

• Sulphur, Aluminium, Chlorine combines a macronutrient, Sulphur, with Aluminium, which is not one of the essential plant nutrients at all; only Chlorine in this set is a genuine micronutrient.

Because Zinc, Iron, and Manganese are the only three elements in the options that are all classified as micronutrients, that set is correct.