Gases referred to as greenhouse gases are

Options

A. `CO_2 , O_2 , NO_2 , NH_3`
B. Chlorofluorocarbon, `CO_2 , NH_3 , N_2`
C. `CH_4, N_2 , CO_2 , NH_3`
D. Chlorofluorocarbon, `CO_2 , CH_4 , NO_2`

Explanation

### Step-by-Step Solution:

1. **Definition of Greenhouse Gases**: Greenhouse gases are gases in the Earth's atmosphere that trap heat. They allow sunlight to enter the atmosphere but prevent some of the heat that the sunlight brings from leaving the atmosphere.

2. **Identification of Common Greenhouse Gases**: The most common greenhouse gases include:
- Carbon Dioxide (CO2)
- Methane (CH4)
- Nitrous Oxide (NO2)
- Ozone (O3)
- Chlorofluorocarbons (CFCs)

3. **Sources of Greenhouse Gases**:
- **Carbon Dioxide (CO2)**: Primarily produced from burning fossil fuels, deforestation, and various industrial processes.
- **Methane (CH4)**: Emitted during the production and transport of coal, oil, and natural gas, as well as from livestock and other agricultural practices.
- **Nitrous Oxide (NO2)**: Comes from agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste.
- **Ozone (O3)**: While it occurs naturally in the atmosphere, ground-level ozone is a result of pollution from vehicles and industrial facilities.
- **Chlorofluorocarbons (CFCs)**: Synthetic compounds used in refrigeration, air conditioning, and aerosol propellants.

4. **Conclusion**: The main greenhouse gases that contribute to global warming and climate change are CO2, CH4, NO2, and CFCs. Among these, CO2 is the most significant contributor.

### Final Answer:
The gases referred to as greenhouse gases include Carbon Dioxide (CO2), Methane (CH4), Nitrous Oxide (NO2), Ozone (O3), and Chlorofluorocarbons (CFCs).

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