_____, _____, _____ and _____ are Greenhouse gases

• A. Carbon Dioxide, CFCs, Methane, Water Vapor
• B. Oxygen, Nitrogen, Argon, Neon
• C. Water Vapor, Oxygen, Nitrogen, Methane
• D. Carbon Dioxide, Oxygen, Argon, Neon

Answer: (A)

Greenhouse gases are the gases in Earth's atmosphere that absorb infrared radiation and trap heat, helping to keep the planet warmer. The gases that fit this role include carbon dioxide, methane, water vapor, and certain synthetic compounds like chlorofluorocarbons. These molecules have vibrational modes that resonate with infrared wavelengths, so they absorb heat as it tries to escape back into space. Water vapor is the most abundant greenhouse gas and acts as an amplifier of warming, while carbon dioxide rises from burning fossil fuels, methane comes from natural and agricultural sources, and CFCs are human-made gases with strong infrared absorption. In contrast, oxygen and nitrogen are diatomic molecules that do not have a permanent dipole moment and thus don’t absorb infrared radiation effectively, and noble gases like argon and neon are inert and also IR-inactive. So the set that includes carbon dioxide, methane, water vapor, and CFCs is the one that reflects greenhouse gases.