Name the most crucial enzyme found in root nodules for `N_(2)`- fixation ? Does it require a special pink coloured pigment for its functioning ? Elaborate.

Explanation

### Step-by-Step Solution:

1. **Identify the Crucial Enzyme**: The most crucial enzyme found in root nodules for nitrogen fixation is **nitrogenase**. This enzyme is essential for the conversion of atmospheric nitrogen (N₂) into ammonia (NH₃).

2. **Function of Nitrogenase**: Nitrogenase catalyzes the reduction of atmospheric nitrogen to ammonia, which is a form that plants can utilize for growth and development. This process is vital for the nitrogen cycle and for providing nitrogen to plants, which cannot use atmospheric nitrogen directly.

3. **Role of Molybdenum and Iron**: Nitrogenase is a complex enzyme that contains molybdenum and iron as key components. These metals are crucial for the enzyme's activity, facilitating the chemical reactions necessary for nitrogen fixation.

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