What do greenhouse gases do when present in the atmosphere?

Greenhouse gases play a crucial role in the Earth's climate system by absorbing and emitting radiation in the thermal infrared range. This interaction with infrared radiation is what allows them to trap heat in the atmosphere, leading to the greenhouse effect. When solar radiation reaches the Earth, some of it is reflected back into space, while the rest is absorbed by the Earth's surface. The Earth, in turn, emits this energy as infrared radiation. Greenhouse gases such as carbon dioxide, methane, and water vapor absorb this infrared radiation and re-radiate it in all directions, including back toward the Earth, which helps in warming the planet.

This process is essential for maintaining a temperature conducive to life; without it, the Earth would be significantly colder. The correct answer points to the fundamental mechanism through which greenhouse gases influence climate and temperature.

Other choices misrepresent the role of greenhouse gases. For example, while some gases in the atmosphere contribute to ozone formation, greenhouse gases themselves are not responsible for creating a protective ozone layer, which is primarily formed by ozone (O3) in the stratosphere. Additionally, greenhouse gases do not block all incoming sunlight; rather, they allow sunlight to enter while trapping heat. Lastly, greenhouse gases do not eliminate air pollution; instead