Which of the following is not a greenhouse gas?

Options

A. `CO_(2)`
B. `CH_(4)`
C. `O_(3)`
D. `N_(2)`

Answer

To determine which of the following is not a greenhouse gas, we first need to understand what greenhouse gases are and identify the common examples of them.

### Step 1: Define Greenhouse Gases
Greenhouse gases are substances in the atmosphere that can absorb and emit infrared radiation. This process is what leads to the greenhouse effect, which warms the Earth's surface.

### Step 2: Identify Common Greenhouse Gases
The most common greenhouse gases include:
- Carbon Dioxide (CO2)
- Methane (CH4)
- Nitrous Oxide (N2O)
- Ozone (O3)
- Water Vapor (H2O)
- Fluorinated Gases

### Step 3: Analyze the Options
Now, let's look at the options provided in the question. We need to identify which one of these is not a greenhouse gas.

- **Carbon Dioxide (CO2)**: This is a major greenhouse gas.
- **Methane (CH4)**: This is also a significant greenhouse gas.
- **Ozone (O3)**: While it is a greenhouse gas, its role is more complex as it can also have cooling effects in the stratosphere.
- **Nitrous Oxide (N2O)**: This is another greenhouse gas.
- **Nitrogen (N2)**: This is not a greenhouse gas. It makes up about 78% of the Earth's atmosphere but does not absorb infrared radiation.

### Step 4: Conclusion
Based on the analysis, the gas that is not a greenhouse gas is **Nitrogen (N2)**.

### Final Answer
The answer to the question "Which of the following is not a greenhouse gas?" is **Nitrogen (N2)**.

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