How does nitrogen occur in the combined state

Explanation

### Step-by-Step Text Solution:

1. **Understanding Nitrogen's Occurrence**: Nitrogen primarily exists in the atmosphere as a diatomic molecule (N₂), but in the combined state, it forms various compounds.

2. **Nitrogen in Rain**: Nitrogen compounds are present in rainwater. During atmospheric processes, nitrogen from the air can combine with oxygen to form nitrogen oxides, which dissolve in rainwater.

3. **Nitrogen in Soil**: In the soil, nitrogen is found in the form of ammonia (NH₃) and ammonium salts (NH₄⁺). These compounds are crucial for plant growth as they are a source of nitrogen for plants.

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