Which of the following is/are greenhouse gas/gases?

The correct answer is All of the above.

Greenhouse gases are gases in Earth's atmosphere that trap heat. They let sunlight pass through the atmosphere, but prevent the heat that the sunlight brings from leaving the atmosphere.

The primary greenhouse gases in Earth's atmosphere are:
1. Water vapour (H₂O): It is the most abundant greenhouse gas and plays a key role in Earth's climate control.
2. Carbon dioxide (CO₂): Released through natural processes such as respiration and volcano eruptions, as well as human activities such as burning fossil fuels.
3. Methane (CH₄): A hydrocarbon gas produced both through natural sources and human activities, including the decomposition of wastes in landfills, agriculture, and ruminant digestion.
4. Nitrous oxide (N₂O) and Ozone (O₃): Other significant greenhouse gases present in the atmosphere.

Since carbon dioxide, methane, and water vapour are all examples of greenhouse gases, the option "All of the above" is correct.