The primary component of the Earth's atmosphere is nitrogen, which makes up about 78% of the atmosphere by volume. Oxygen follows as the second most abundant gas, comprising around 21%. Other gases, such as argon, carbon dioxide, and trace amounts of others, make up the remaining percentage. The atmosphere plays a crucial role in protecting life on Earth by filtering harmful solar radiation, moderating temperature, and facilitating the water cycle. The balance of gases in the atmosphere is essential for maintaining ecosystems and regulating the planet's climate.