What air contains and in what proportion it contains?

Air is made up of: 78% nitrogen 20% oxygen 0.93% argon 0.04% carbon dioxide And about 1% water vapor which varies with humidity. There are small trace amounts of other gasses including radioactive...

Its an air bag. Yes, it has air in it. When a car crash happens, the bag fills up with air very quickly.

In theory, a vacuum would contain no air, but in reality, it is very difficult to create a pure vacuum. Also, any area that was completely filled with another element would contain no air.

Mostly Nitrogen, little bit of helium and hydrogen. Carbon Dioxide, oxigen and methane. They are the main ones. Oxygen and Methane are the smallest.

Air on Earth is mostly Nitrogen, followed by oxygen, and then carbon dioxide and trace gasses