Solution:The percentage of oxygen in the atmosphere is 21% and carbon dioxide is 0.03%.
Air is a mixture of different gases. All living things require air to survive. Components of air are oxygen, water vapour, nitrogen, carbon dioxide, dust and smoke. Air contains water vapours. About 78.9% of total air is nitrogen. Oxygen is 21% of total air. Carbon dioxide is about 0.03-0.04% of total air. Dust and smoke are always present in the air.