Which of the following is a microelement ?

Options

A. Chlorine
B. Hydrogen
C. Nitrogen
D. Oxygen

Answer

To determine which of the given options is a microelement, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Microelements**:
- Microelements, also known as micronutrients, are essential elements that are required by plants in very small quantities. They play crucial roles in various physiological functions.

2. **List the Given Options**:
- The options provided are:
- Chlorine
- Hydrogen
- Nitrogen
- Oxygen

3. **Analyze Each Option**:
- **Hydrogen**: This is a major element and is abundant in plants, thus not a microelement.
- **Nitrogen**: This is also a primary nutrient that plants require in larger amounts, so it is not a microelement.
- **Oxygen**: Similar to hydrogen and nitrogen, oxygen is abundant and essential in larger quantities for plant respiration and photosynthesis.
- **Chlorine**: This element is required by plants in very small amounts, making it a microelement.

4. **Conclusion**:
- Based on the analysis, the only element from the options that qualifies as a microelement is **Chlorine**.

### Final Answer:
- The microelement among the given options is **Chlorine**.

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