Which of the following is not a greenhouse gas?

Options

A. `CO_(2)`
B. `CH_(4)`
C. Chloro fluoro carbons
D. `O_(2)`

Answer

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

### Step 1: Define Greenhouse Gases
Greenhouse gases are gases that can absorb and emit infrared radiation, contributing to the greenhouse effect. This effect is crucial for maintaining the Earth's temperature.

### Step 2: Identify Common Greenhouse Gases
Some primary greenhouse gases include:
- Water Vapor (H2O)
- Carbon Dioxide (CO2)
- Methane (CH4)
- Nitrous Oxide (N2O)
- Ozone (O3)
- Chlorofluorocarbons (CFCs)

### Step 3: Analyze the Options
Now, we need to analyze the options provided in the question to identify which one is not a greenhouse gas. Based on our knowledge:
- Water Vapor: Greenhouse gas
- Carbon Dioxide: Greenhouse gas
- Methane: Greenhouse gas
- Nitrous Oxide: Greenhouse gas
- Ozone: Greenhouse gas
- Chlorofluorocarbons: Greenhouse gas
- Oxygen (O2): Not a greenhouse gas

### Step 4: Conclusion
From the analysis, it is clear that Oxygen (O2) does not have the properties of a greenhouse gas, as it does not significantly absorb or emit infrared radiation.

### Final Answer
The gas that is not a greenhouse gas is **Oxygen (O2)**.

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