What is the atmosphere primarily composed of?

The atmosphere is primarily composed of gases surrounding the Earth, which include nitrogen (approximately 78%), oxygen (about 21%), and trace amounts of other gases such as argon, carbon dioxide, and water vapor. This composition is crucial for a variety of reasons, including supporting life through the availability of oxygen and regulating climate and weather patterns.

The distinction from solid elements, liquid water, and minerals from the lithosphere is important because these components do not constitute the atmosphere. Solids and minerals are part of the Earth's crust and geology, while liquid water is primarily found in oceans, rivers, and lakes rather than in the gaseous envelope surrounding the planet. Knowing these details provides a deeper understanding of the Earth's systems and how the atmosphere interacts with other spheres, such as the hydrosphere and lithosphere.