Explanation

The percentage of oxygen in the air is about 20.95%.

The air is made up of many gases, including oxygen, nitrogen, argon, and carbon dioxide

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Nitrogen

Nitrogen is the most abundant gas in the air, making up about 78% of it. 

Argon

Argon is the third most abundant gas in the air, making up about 0.93% of it. 

Carbon dioxide

Carbon dioxide is present in trace amounts in the air, making up about 0.04% of it.