Which of the following is a macronutrient for plants?

• A. Nitrogen
• B. Iron
• C. Manganese
• D. Copper

Answer: (A)

Plants need nutrients in two main groups: macronutrients and micronutrients. Macronutrients are required in larger amounts for growth and essential processes. Nitrogen is a primary macronutrient because it is a major building block of amino acids, proteins, chlorophyll, and nucleic acids, all crucial for growth, leaf development, and photosynthesis. Without enough nitrogen, plants struggle to synthesize proteins and chlorophyll, leading to stunted growth and yellowing leaves.

The other elements listed are micronutrients, needed in much smaller amounts and supporting various enzyme functions and metabolic steps rather than forming the main structural or functional components of the plant. Iron, manganese, and copper play roles in enzyme activity and chlorophyll formation, but they do not meet the quantity criterion that defines macronutrients.