Which criteria allow biologists to divide chemicals into macronutrients and micronutrients?

The requirement of different nutrients, divide them into 2 categories.

Explanation:

On the basis of requirement of nutrients in our food, the chemicals are divided into 2 types - macronutrients, and macronutrients.

Nutrients are the molecules present in the food nourishes the living organisms. The macronutrients are needed in large quantities and they provide energy to the organism.

There are 3 major macronutrients present in every kind of food - proteins, fats, and carbohydrates.  

On the other hand, micronutrients are required very less amount to the animals. But they are important for nourishment of the body, but their quantity is very less. Example of micronutrients are vitamins, minerals, manganese, iron, potassium, etc.

Therefore, it is told one should take balance diet to get all the nutrients.