Which of the following micronutrients is essential for activation of urease, the enzyme involved in nitrogen metabolism ?

Options

A. Boron
B. Molybdenum
C. Zinc
D. Nickel

Explanation

To determine which micronutrient is essential for the activation of urease, an enzyme involved in nitrogen metabolism, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Enzyme and Its Function**:
- Urease is an enzyme that catalyzes the hydrolysis of urea into ammonia and carbon dioxide. This process is crucial for nitrogen metabolism in plants.

2. **List the Given Micronutrients**:
- The options provided are boron, molybdenum, zinc, and nickel.

3. **Research Each Micronutrient's Role**:
- **Boron**: Essential for plant growth and development, involved in sugar transport and calcium uptake, but not directly related to urease activation.
- **Molybdenum**: Acts as a cofactor for various enzymes, including xanthine dehydrogenase, but not specifically known for urease activation.
- **Zinc**: Important for various enzymes, including carbonic anhydrase and glutamate dehydrogenase, but not specifically for urease.
- **Nickel**: Recognized as a component of urease and is essential for its activation. It is absorbed by plants as a divalent cation and is crucial for nitrogen metabolism.

4. **Conclusion**:
- Based on the roles of these micronutrients, nickel is the only one that is essential for the activation of urease.

### Final Answer:
The correct answer is **Nickel**.

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