Certified Arborist Practice Test

Micronutrients are elements required by plants in smaller quantities compared to macronutrients, but they are nonetheless essential for various physiological functions. The correct choice includes copper, chlorine, and boron, which are all classified as micronutrients.

Copper is important for photosynthesis and enzyme activation, helping to facilitate plant metabolic processes. Chlorine plays a vital role in photosynthesis and maintaining osmotic pressure in plant cells, while boron is essential for cell wall formation and reproductive health in plants. Each of these micronutrients supports critical physiological processes that contribute to healthy plant growth.

The other options consist of macronutrients or elements that do not fit the definition of micronutrients. Nitrogen, phosphorus, and potassium are primary macronutrients crucial for plant growth and development, while calcium, magnesium, and sulfur also function as secondary macronutrients, required in larger amounts than micronutrients. Sodium, although important in some contexts, does not typically fall into the category of essential nutrients for all plants, and carbon is a primary element involved in photosynthesis and not classified as a nutrient in the same context as the others listed.