Criterion of essentiality is applicable to:

Options

A. Only microelements
B. Only macronutrients
C. Both micro and macronutrients
D. All elments found is soil

Answer

To answer the question regarding the criterion of essentiality, we will follow a structured approach:

### Step-by-Step Solution:

1. **Understanding the Criterion of Essentiality**:
- The criterion of essentiality refers to the specific requirements that an element must meet to be considered essential for plant growth and development.

2. **First Criterion**:
- An element must be absolutely necessary for supporting normal growth and reproduction in plants. If the element is absent, the plant cannot complete its life cycle or produce seeds.

3. **Second Criterion**:
- The requirement for the element must be specific. This means that the element cannot be substituted or replaced by another element. If there is a deficiency of this essential element, no other element can fulfill its role.

4. **Third Criterion**:
- The element must be directly involved in the metabolism of the plant. This means that it plays a crucial role in biochemical processes necessary for the plant's survival and growth.

5. **Classification of Essential Elements**:
- Essential elements are classified into two categories: macronutrients and micronutrients. There are a total of 17 essential elements, and both categories are necessary for plant health.

6. **Conclusion**:
- Based on the criteria outlined, the criterion of essentiality is applicable to both macronutrients and micronutrients. Therefore, the correct answer to the question is that the criterion of essentiality is applicable to both macronutrients and micronutrients.

### Final Answer:
The criterion of essentiality is applicable to both macronutrients and micronutrients.

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