Which metal ion is a constituent of chlorophyll?

Options

A. Iron
B. Copper
C. Manesium
D. Zinc

Explanation

**Step-by-Step Solution:**

1. **Understanding Chlorophyll**: Chlorophyll is a green pigment found in plants that is crucial for photosynthesis. It allows plants to absorb sunlight, which is essential for converting light energy into chemical energy.

2. **Identifying Metal Ions**: The question asks for a metal ion that is a constituent of chlorophyll. The options provided are iron, copper, magnesium, and zinc.

3. **Analyzing the Options**:
- **Iron**: While iron is an important element in plants, it is not a part of the chlorophyll molecule. It is found in plastids and is involved in various metabolic processes.
- **Copper**: Copper is also essential for plant growth but does not form part of chlorophyll.
- **Zinc**: Zinc is another trace element that is important for plant health but is not a component of chlorophyll.
- **Magnesium**: Magnesium is a central atom in the chlorophyll molecule. It is essential for the structure of chlorophyll and plays a key role in photosynthesis.

4. **Conclusion**: The metal ion that is a constituent of chlorophyll is **magnesium**.

5. **Final Answer**: Therefore, the correct answer to the question is **magnesium**.

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