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

Nitrogen is recognized as a macronutrient, which distinguishes it from the others listed in the options. Macronutrients are required in larger quantities by plants and are essential for crucial biological processes. Nitrogen plays a vital role in the synthesis of amino acids, nucleic acids, and chlorophyll, thereby influencing protein formation and overall plant growth.

In contrast, zinc, copper, and boron are classified as micronutrients. These elements are required in smaller amounts but are nonetheless critical for plant health and functioning. They contribute to various physiological processes, such as enzyme activity and plant metabolism. Understanding the distinction between macronutrients and micronutrients is fundamental in plant nutrition, ensuring that plants receive the correct balance of nutrients for optimal growth.