Which of the following is a Greenhouse gas? 

All of the above 

The correct answer is option 4. All of the above.

All of the above—Carbon dioxide \((CO_2)\), Methane \((CH_4)\), and Chlorofluorocarbon \((CF_2Cl_2)\)—are greenhouse gases. Therefore, the correct option is All of the above

1. Carbon Dioxide \((CO_2)\):

Carbon dioxide is one of the most significant greenhouse gases. It is naturally present in the Earth's atmosphere and is released through various natural and human activities, including the burning of fossil fuels and deforestation.

2. Methane \((CH_4)\):

Methane is another potent greenhouse gas. It is released during the production and transport of coal, oil, and natural gas. Agricultural practices, such as rice cultivation and livestock digestion, also contribute to methane emissions.

3. Chlorofluorocarbon \((CF_2Cl_2)\):

Chlorofluorocarbons (CFCs), including \(CF_2Cl_2\), are synthetic compounds that were once widely used in refrigeration, air conditioning, and aerosol propellants. While they are not as abundant as \(CO_2\) and \(CH_4\), they are potent greenhouse gases and have been largely phased out due to their role in ozone depletion.

Greenhouse gases trap heat in the Earth's atmosphere, contributing to the greenhouse effect. While the greenhouse effect is essential for maintaining a habitable temperature on Earth, an increase in the concentration of these gases, largely due to human activities, has led to enhanced global warming and climate change. Efforts to address climate change often focus on mitigating the emissions of greenhouse gases and transitioning to more sustainable practices.