Which of the following locations acts as the reservoir for nitrogen cycle?

Options

A. Atmosphere
B. Sedimentary bedrock
C. Soil
D. Fossilised plant and animal remains

Answer

To determine which location acts as a reservoir for the nitrogen cycle, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Nitrogen Cycle**: The nitrogen cycle is a biogeochemical cycle that describes the transformation and movement of nitrogen through the atmosphere, soil, and living organisms.

2. **Identify the Type of Cycle**: The nitrogen cycle is classified as a gaseous biogeochemical cycle. This means that nitrogen exists in gaseous forms (like N₂) in the atmosphere and is exchanged between different reservoirs.

3. **Identify Reservoirs in the Nitrogen Cycle**: In gaseous cycles, the primary reservoirs are typically the atmosphere and hydrosphere. For nitrogen, the atmosphere is the largest reservoir, as it contains about 78% nitrogen gas.

4. **Evaluate the Options**:
- **Atmosphere**: This is the primary reservoir for nitrogen.
- **Sedimentary Bedrock**: This is more relevant to the phosphorus cycle.
- **Soil**: While soil contains nitrogen, it is not the primary reservoir compared to the atmosphere.
- **Fossil Plant and Animal Remains**: These are more associated with the carbon cycle.

5. **Conclusion**: Based on the analysis, the correct answer is that the atmosphere acts as the reservoir for the nitrogen cycle.

### Final Answer:
The atmosphere is the reservoir for the nitrogen cycle.

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