Question

Which of the following lists includes only greenhouse gases that significantly contribute to Earth's greenhouse effect?
A. Oxygen (O2), Nitrogen (N2), Argon (Ar)
B. Carbon dioxide (CO2), Methane (CH4), Water vapor (H2O)
C. Helium (He), Neon (Ne), Krypton (Kr)
D. Ozone (O3), Sulfur dioxide (SO2), Sodium chloride (NaCl)




Question 7 - Multiple Choice
Points: 1
Methane (CH4) is a potent greenhouse gas because:
A. It absorbs infrared radiation more strongly per molecule than CO2 and can be emitted from wetlands and fossil fuel extraction.
B. It reflects sunlight back to space, cooling the surface.
C. It permanently removes water vapor from the atmosphere.
D. It increases Earth's orbital eccentricity.




Question 8 - Multiple Choice
Points: 1
If atmospheric greenhouse gas concentrations double, the immediate effect on Earth's energy balance would be:
A. No change because greenhouse gases do not affect energy balance
B. A net increase in incoming solar radiation at the top of the atmosphere
C. A reduction in outgoing longwave radiation to space, leading to an energy surplus and warming until a new equilibrium is reached
D. Immediate and equal cooling of the atmosphere and surface






Question 9 - Multiple Choice
Points: 1
Which human action would most directly reduce the rate of increase in atmospheric carbon dioxide?
A. Planting trees and protecting forests to increase carbon uptake by ecosystems
B. Increasing the use of single-use plastics without recycling
C. Clearing more land for agriculture by burning forests
D. Banning bicycles in cities




Question 10 - Multiple Choice
Points: 1
Which sentence correctly links greenhouse gases to feedbacks that amplify warming?
A. Warming reduces water vapor in the atmosphere, which decreases the greenhouse effect and cools the planet.
B. Warming can increase water vapor (a greenhouse gas), which enhances the greenhouse effect and leads to further warming — a positive feedback.
C. Increased warming always leads to increased volcanic eruptions that remove greenhouse gases.
D. Feedbacks never change the magnitude of warming once greenhouse gas levels are set.

Answer 1

Q6: B — Carbon dioxide (CO2), Methane (CH4), Water vapor (H2O).

Q7: A — It absorbs infrared more strongly per molecule than CO2 and is emitted from wetlands and fossil fuel extraction.

Q8: C — Reduction in outgoing longwave radiation, causing an energy surplus and warming until a new equilibrium.

Q9: A — Planting/protecting forests increases carbon uptake and slows atmospheric CO2 rise.

Q10: B — Warming increases atmospheric water vapor, enhancing the greenhouse effect (positive feedback).