Which of the following is NOT considered a micronutrient essential for plant growth?

Nitrogen is considered a macronutrient rather than a micronutrient. Macronutrients are required by plants in larger quantities compared to micronutrients, which are only needed in trace amounts. While elements such as zinc, copper, and boron are classified as micronutrients due to their critical roles in various physiological functions and their necessity in smaller doses for plant growth and development, nitrogen stands out as a primary component of proteins and nucleic acids, making it essential in larger amounts for overall plant health. Thus, it is categorized distinctly from the micronutrients listed in the other choices. Understanding this distinction helps clarify the different roles and requirements of nutrients in plant biology.