Name three micronutrients essential to plants.

• A. Iron (Fe), Manganese (Mn), and Zinc (Zn)
• B. Nitrogen (N), Phosphorus (P), and Potassium (K)
• C. Calcium (Ca), Magnesium (Mg), and Sulfur (S)
• D. Carbon (C), Hydrogen (H), and Oxygen (O)

Answer: (A)

Micronutrients are the trace elements that plants need in very small amounts, but they’re essential for enzyme function and key physiological processes. Iron, manganese, and zinc fit this category. Iron is vital for chlorophyll synthesis and electron transport in photosynthesis, manganese helps with the water-splitting step in photosystem II and acts as a cofactor for various enzymes, and zinc serves as a cofactor for many enzymes and helps regulate growth and gene expression. The other groups are macronutrients or major elements required in larger quantities: nitrogen, phosphorus, and potassium support overall growth and development; calcium, magnesium, and sulfur are also needed in bigger amounts for structural roles and metabolic functions; carbon, hydrogen, and oxygen form the backbone of organic molecules and are typically needed in the largest quantities, coming from air and water rather than soil minerals. So iron, manganese, and zinc are the true micronutrients among the options.