Assessment and Qualifications Alliance (AQA) GCSE Chemistry Paper 2 Practice Exam 2026 - Free GCSE Chemistry Practice Questions and Study Guide

The primary role of greenhouse gases in the atmosphere is to maintain a temperature on Earth that is high enough to support life. Greenhouse gases, such as carbon dioxide, methane, and water vapor, allow sunlight to enter the Earth's atmosphere but trap some of the outgoing infrared radiation emitted by the Earth's surface, leading to a warming effect known as the greenhouse effect. This process is essential for creating and sustaining an environment where various forms of life can thrive.

The other options, while related to atmospheric processes, do not accurately reflect the primary function of greenhouse gases. For instance, depleting the ozone layer is associated with substances like chlorofluorocarbons, rather than greenhouse gases. Filtering harmful radiation is primarily the role of ozone in the stratosphere, not greenhouse gases, which are involved in heat retention. Enhancing meteorological phenomena can occur due to climate change impacted by greenhouse gas levels, but it is not their main role. Thus, the answer about maintaining temperature is fundamental to understanding the importance of greenhouse gases in supporting life on Earth.