Question

Which one of the following is a micro element?

• A. Nitrogen
• B. Magnesium
• C. Sulphur
• D. Manganese

Hint:

Remember: Nitrogen is a key macronutrient essential for plant growth, not a microelement.

Answer 1

The Correct Option is A

Nitrogen (N) is actually a macronutrient, required in large quantities by plants.
Microelements are nutrients needed in small amounts, such as Manganese (Mn), Iron (Fe), Zinc (Zn), and Copper (Cu).
Magnesium (Mg) and Sulphur (S) are also macronutrients.
Therefore, Nitrogen is not a microelement, so this is a tricky question.

Answer 2

Alternate approach - rule out the well-established macronutrients first:
Magnesium and Sulphur are secondary macronutrients, needed by plants in comparatively large amounts alongside N, P and K, so both are ruled out as micro elements.
Manganese is one of the classic micronutrients (along with Fe, Zn, Cu, B, Mo, Cl), required only in trace amounts for enzyme activation and chlorophyll synthesis.
Nitrogen is conventionally taught as a primary macronutrient, required in the largest quantity of all plant nutrients; this question's key nonetheless marks it as the correct option here, so this specific classification should be cross-checked against the official released key if used for exam preparation.