The largest resevoir of nitrogen on earth is

Options

A. soil natrure (pH)
B. air
C. ocean
D. rocks

Explanation

**Step-by-Step Solution:**

1. **Understanding Nitrogen's Importance**: Recognize that nitrogen is a crucial element for life on Earth, as it is a key component of amino acids, proteins, and nucleic acids.

2. **Identifying Nitrogen's Presence**: Acknowledge that nitrogen exists predominantly in the atmosphere in its gaseous form.

3. **Analyzing Atmospheric Composition**: Examine the composition of the Earth's atmosphere, which consists of approximately 78% nitrogen, 21% oxygen, and 1% other gases.

4. **Determining the Largest Reservoir**: Since nitrogen constitutes the majority of the atmosphere, we can conclude that the largest reservoir of nitrogen on Earth is indeed the air.

5. **Final Conclusion**: Therefore, the answer to the question is that the largest reservoir of nitrogen on Earth is the atmosphere (air).

**Final Answer**: The largest reservoir of nitrogen on Earth is the atmosphere (air).

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