Which of the following is NOT considered a macronutrient?

Macronutrients are elements that plants require in larger quantities for their growth and development. The primary macronutrients typically include nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur. These nutrients play crucial roles in various physiological processes, such as photosynthesis, cell division, and overall plant structure and health.

In this context, nitrogen, phosphorus, and calcium are all classified as macronutrients because they are essential for plant growth in significant amounts. Copper, however, is categorized as a micronutrient. While copper is important for plant health, it is needed in much smaller quantities compared to macronutrients. It plays various roles such as aiding in photosynthesis, enzyme function, and the formation of proteins, but the requirement for copper in a plant's diet is relatively minimal. This distinction is key in understanding the roles and classifications of nutrients in plant science.