Which of the following gases are known to contribute to the greenhouse effect?

The contribution of gases to the greenhouse effect is essential for understanding climate change and the dynamics of Earth's atmosphere. Water vapor and carbon dioxide are both greenhouse gases that play significant roles in trapping heat in the Earth’s atmosphere.

Water vapor is the most abundant greenhouse gas and contributes to the natural greenhouse effect by absorbing infrared radiation emitted from the Earth's surface. This process helps maintain temperatures necessary for life. Carbon dioxide, while less abundant than water vapor, is a critical greenhouse gas because of human activities such as burning fossil fuels and deforestation, which have significantly increased its concentrations over time.

The other choices do not relate directly to the greenhouse effect. Oxygen and nitrogen are major components of the atmosphere, but they do not have greenhouse properties. Argon and helium are noble gases that also do not contribute to the greenhouse effect. Lastly, while coal and natural gas are fossil fuels that release greenhouse gases upon combustion, they are not gases themselves; thus, they do not directly contribute in their raw form.

In summary, water vapor and carbon dioxide are both crucial because they effectively trap heat, influencing the climate and making them central to discussions about global warming and environmental policies.