What percentage of the air we breathe is made up of oxygen?
- (1). 16%
- (2). 21%
- (3). 26%
- (4). 31%
Answer B: 21%
The air you breathe is made up of lots of other things besides oxygen! Oxygen only makes up about 21% of air. About 78% of the air you breathe is made up of another gas called nitrogen. There are also tiny amounts of other gases like argon, carbon dioxide and methane. Plant and animal life on earth can’t survive without air.