Which of the following is a macronutrient for plants?

• A. Calcium
• B. Iron
• C. Zinc
• D. Manganese

Answer: (A)

Plants need minerals in different amounts. Macronutrients are required in larger quantities to build structures and support growth, while micronutrients are needed only in trace amounts for specific biochemical roles. Calcium fits the macronutrient category because it is needed in relatively larger amounts to strengthen cell walls and membranes and to participate in signaling within the plant. It helps form the calcium-pectate bonds that stabilize cell walls, contributing to overall plant rigidity and function. Iron, zinc, and manganese, on the other hand, are required in much smaller amounts and mainly serve as enzyme cofactors or for particular metabolic processes. So calcium is the macronutrient among these options.