Final answer:
The Earth's atmosphere is mostly composed of three gases: nitrogen (78%), oxygen (21%), and argon (0.93%), with traces of other gases like carbon dioxide (0.04%). These constant gases are largely responsible for climate regulation and supporting life by creating a breathable environment and contributing to the greenhouse effect.
Step-by-step explanation:
The majority of the Earth's atmosphere is made up of three key constant gases: nitrogen, oxygen, and argon. About 78% of the atmosphere is comprised of nitrogen, which serves as the solvent of the air's gas-gas solution. Oxygen comes next, making up around 21%, and is vital for aerobic respiration and combustion processes. Argon, although it represents a much smaller portion of the atmosphere at approximately 0.93%, is the third most prevalent gas. Other trace gases, including carbon dioxide and water vapor, also play significant roles despite their relatively low concentrations, like CO2's involvement in climate regulation through the greenhouse effect.
Carbon dioxide, although present in abundance of about 0.04%, has a critical impact on the Earth's temperature and contributes to the greenhouse effect that maintains a habitable climate. The atmosphere's composition remains remarkably uniform below about 100 kilometers above the Earth's surface, beyond which lighter gases become relatively more abundant due to diffusion and photochemical processes. The troposphere is the lowest level of the atmosphere and is responsible for maintaining conditions conducive for life on the planet's surface