Amount of nitrogen fixed electrochemically and photo chemically is

Options

A. `140 mg/m^2 /yr`
B. `78 mg/m^2 /yr`
C. `35 mg/m^2 /yr`
D. `15 mg/m^2 /yr`

Explanation

### Step-by-Step Solution:

1. **Understanding Nitrogen Fixation**:
- Nitrogen (N2) is a major component of the atmosphere, making up about 78%. However, it is in a stable form due to the triple bonds between nitrogen atoms, making it difficult for plants and animals to utilize directly.

2. **Importance of Nitrogen**:
- Nitrogen is essential for the growth of plants and animals. Plants require nitrogen to synthesize proteins and nucleic acids, while animals obtain nitrogen by consuming plants.

3. **Methods of Nitrogen Fixation**:
- Nitrogen can be fixed through various methods, including biological processes (like those involving nitrogen-fixing bacteria), electrochemical processes, and photochemical processes.

4. **Electrochemical Nitrogen Fixation**:
- In industrial settings, nitrogen is fixed electrochemically through processes like the Haber-Bosch process, where nitrogen is converted into ammonia (NH3). This process is crucial for producing fertilizers.

5. **Photochemical Nitrogen Fixation**:
- Photochemical fixation occurs naturally through lightning, where the energy from lightning breaks the nitrogen bonds, allowing nitrogen to combine with oxygen to form nitrates, which can be utilized by plants.

6. **Quantifying Nitrogen Fixation**:
- The question asks for the amount of nitrogen fixed electrochemically and photochemically. According to the information provided, the total amount of nitrogen fixed through these processes is approximately **35 mg per meter square per year**.

### Final Answer:
- The amount of nitrogen fixed electrochemically and photochemically is **35 mg per meter square per year**.

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