Which of the following is NOT considered a macronutrient?

Zinc is not classified as a macronutrient; rather, it is considered a micronutrient. Macronutrients are the nutrients that plants require in larger quantities for growth and development. These include nitrogen, calcium, and potassium, which play critical roles in various physiological processes such as protein synthesis, cell structure, and energy transfer.

In contrast, micronutrients like zinc are essential for plant health but are required in much smaller amounts. They contribute to different functions, such as enzyme activity and chlorophyll production, but do not have the same volume of necessity in plant nutrition as macronutrients do. Understanding this distinction is crucial for effective nutrient management in agriculture, as it helps in tailoring fertilization practices based on the specific needs of crops.