Answer:
In air the percentage of oxygen gas- 21%
Explanation:
The composition of gases in air are as follows-
Nitrogen- In air Nitrogen gas present in abundance. 78% of air is Nitrogen gas. In living organisms nitrogen is present in nucleic acid and amino acids.
Oxygen-In air the percentage of oxygen is 21%.Oxygen is most important components of air , it is needed for cellular respiration and for breathing. It also forms cellular molecules like- carbohydrates ,protein, fats , lipids etc. Oxygen is highly reactive gas and for combustion , it is also important.
Argon- This is the third most abundant component in air . The percentage in air is-0.93%. Argon is a noble gas.
Carbon dioxide and small amount of gases- Carbon dioxide is present in atmosphere as a trace element of about 0.04% with other gases and water vapour. It takes part in respiration. It is present in trace amount in air. Because of deforestation, combustion it is increasing day by day and causing air pollution.
