Q1Multiple choice
Air is a mixture of various gases. One of the gases is 21% part of the air and is essential for the survival of human beings. This gas is
- (a)nitrogen
- (b)oxygen
- (c)ozone
- (d)argon
Show answer
(b) oxygen
Air is a mixture of various gases. One of the gases is 21% part of the air and is essential for the survival of human beings. This gas is
(b) oxygen