Explanation
Answer: C. Copper
Copper is a trace element (also called a micronutrient) required by plants in very small amounts. It is essential for enzyme function and chlorophyll production.
Other Options:
A. Potassium – A macronutrient, needed in large quantities for enzyme activation and osmoregulation.
B. Sodium – Not essential for most plants; some plants use it, but it is not a trace element.
D. Phosphate – Supplies phosphorus, a macronutrient vital for energy transfer (ATP).
E. Nitrate – Supplies nitrogen, another macronutrient needed for amino acids and proteins.
