The amount of mineral elements like iron, copper and zinc are required by the plants is

Options

A. Equal to 100 mmole `kg^-1` of dry matter
B. Mnore than 10 mmole `kg^-1` of dry matter
C. Less than 10 mmol `kg^-1` of dry matter
D. Equal to 1.0 mmole `kg^-1` of dry matter

Answer

To solve the question regarding the amount of mineral elements like iron, copper, and zinc required by plants, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Elements**: The question mentions three mineral elements: iron, copper, and zinc.

2. **Classify the Elements**: These elements are classified as microelements (or trace elements) because they are required by plants in small quantities, as opposed to macroelements which are needed in larger amounts.

3. **Understand the Requirement**: The question asks for the specific amount of these microelements required by plants. Generally, microelements are needed in quantities less than 10 millimoles per kilogram of dry matter.

4. **Evaluate the Options**:
- **Option A**: 100 millimoles per kilogram - This is too high for microelements.
- **Option B**: More than 10 millimoles per kilogram - This also suggests a higher requirement than what is typical for microelements.
- **Option C**: Less than 10 millimoles per kilogram - This aligns with the known requirement for microelements.
- **Option D**: Equal to 1.0 mole per kilogram - This is excessively high and not applicable to microelements.

5. **Select the Correct Answer**: Based on the classification and typical requirements of these elements, the correct answer is **Option C: less than 10 millimoles per kilogram of dry matter**.

### Final Answer:
The amount of mineral elements like iron, copper, and zinc required by plants is **less than 10 millimoles per kilogram of dry matter**.

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