Answer:
a. micronutrients
Step-by-step explanation:
For their growth and development, living things need various minerals. Regardless of their importance, but depending on the amount required, these nutrients are called macro or micronutrients. The main or primary macronutrients are nitrogen, phosphorus and potassium, which are required the most, and calcium, magnesium and sulfur are considered secondary macronutrients, just because they are less required.
Molybdenum, zinc, boron, copper, chlorine, cobalt, nickel, manganese, iron and selenium are required in much lower quantities than macronutrients, being called micronutrients. The differential demand can be explained because macronutrients are mainly involved in the formation of structural molecules, while micronutrients make up the enzyme molecules, being essential for enzymatic functions.