Multiple choice Among the following plant nutrients, which is a macro-nutrient? Manganese Calcium Chlorine Copper Reveal answer Fill a bubble to check yourself B Correct answer Explanation Macronutrients are elements plants need in large amounts. Primary macronutrients are N, P, K. Secondary macronutrients include Ca (calcium), Mg, and S. Manganese, chlorine, and copper are all micronutrients needed in trace amounts.