Select incorrect statement w.r.t micronutrients.

Options

A. Become toxic in excess.
B. Involved in activation of enzyme
C. Involved in building of protoplastic constituents
D. Concentration is less then 10 millimole ` kg ^(-1) ` of dry matter.

Answer

To solve the question "Select the incorrect statement w.r.t micronutrients," we will analyze the characteristics of micronutrients based on the provided information.

### Step-by-Step Solution:

1. **Definition of Micronutrients**: Micronutrients are essential elements required by plants in small quantities, typically less than 10 millimoles per kg of soil.

2. **Functions of Micronutrients**:
- Micronutrients play a crucial role in plant growth and development.
- They are involved in the formation of protoplasm, which is essential for cellular structure and function.

3. **Role in Enzyme Activation**: Micronutrients serve as cofactors for enzymes, meaning they are necessary for the activation of certain enzymes, enhancing their activity.

4. **Toxicity in Excess**: It is stated that micronutrients can become toxic when present in excess. This is a critical point because it indicates that while they are needed in small amounts, too much can be harmful.

5. **Identifying the Incorrect Statement**: The statement that "micronutrients do not become toxic when they are present in excess" contradicts the previously mentioned point about toxicity. Thus, this statement is incorrect.

### Conclusion:
The incorrect statement with respect to micronutrients is that they do not become toxic when present in excess.

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