The concentration of elements such as carbon and nitrogen in plants is

Options

A. Above 10 millimole `kg^(-1)` of dry matter
B. Less than 10 millimole ` kg ^(-1) ` of dry matter
C. Equal to 10 millimole ` kg ^(-1) ` of dry matter.
D. Between 1 - 10 millimole ` g ^(-1)` of dry matter.

Answer

To answer the question regarding the concentration of elements such as carbon and nitrogen in plants, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Nutrient Classification**:
- Nutrients in plants are classified into two main categories based on the concentration required: macronutrients and micronutrients.

2. **Defining Macronutrients**:
- Macronutrients are elements that plants require in larger quantities. The concentration of macronutrients is typically greater than 10 millimoles per kilogram (mmol/kg) of dry matter.

3. **Defining Micronutrients**:
- Micronutrients, on the other hand, are required in smaller quantities, with concentrations less than 10 mmol/kg of dry matter.

4. **Identifying Carbon and Nitrogen**:
- Carbon and nitrogen are both essential elements for plant growth. They play critical roles in various biological processes, including photosynthesis and protein synthesis.

5. **Conclusion**:
- Since carbon and nitrogen are required in concentrations above 10 mmol/kg of dry matter, they are classified as macronutrients.

### Final Answer:
The concentration of elements such as carbon and nitrogen in plants is above 10 mmol/kg of dry matter, indicating that they are macronutrients.

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