What are macro-nutrients and why are they called macro-nutrients

Q. No. 1:

What are macro-nutrients and why are they called macro-nutrients?

Ans:

Macro-nutrients are those nutrients which are required in large quantities for growth and development of plants. Since they are required in large quantities, they are known as macro-nutrient. The six macro-nutrients required by plants are nitrogen, phosphorus, potassium, calcium, magnesium, and sulphur.