Provide definitions/explanations for the following:
$(1)$ Macronutrients
$(2)$ Micronutrients

(N/A) $(1)$ Macronutrients: These are elements present in plant tissues in large amounts,typically in excess of $10 \text{ mmol } kg^{-1}$ of dry matter.
$(2)$ Micronutrients: These are elements required by plants in very small amounts,typically less than $10 \text{ mmol } kg^{-1}$ of dry matter.