Which of the following nutrients is classified as a micronutrient?

Micronutrients are essential elements that plants require in smaller amounts compared to macronutrients. Copper is classified as a micronutrient because it plays a critical role in various physiological functions in plants, such as photosynthesis, respiration, and the synthesis of lignin and other important compounds. It is required in trace amounts but is vital for enzymatic reactions and plant health.

In contrast, calcium, nitrogen, and potassium are classified as macronutrients. Calcium is vital for cell wall structure and stability, nitrogen is essential for protein synthesis and overall plant growth, and potassium is crucial for regulating water retention, enzyme activation, and photosynthesis efficiency. Understanding the roles of these nutrients helps in effective nutrient management strategies to promote plant growth and yield.