Air is predominantly composed of:

Air is predominantly composed of oxygen (O2) and nitrogen (N2), which together make up about 99% of the Earth's atmosphere. Nitrogen is the most abundant gas, comprising nearly 78% of the atmosphere, while oxygen accounts for about 21%. The presence of these two gases is crucial for life on Earth, as nitrogen is essential for plant growth and oxygen is vital for the respiration of living organisms.

While carbon dioxide (CO2) and methane (CH4) are also present in the atmosphere, they exist in much smaller quantities compared to nitrogen and oxygen. Carbon dioxide is important for photosynthesis and is a greenhouse gas, while methane is a potent greenhouse gas but is found in even lower concentrations.

Therefore, recognizing that oxygen and nitrogen are the primary constituents of air enhances the understanding of the atmosphere's composition and the roles these gases play in supporting life and various environmental processes.