What percentage of air is accounted by carbon dioxide, water vapour, dust particles and other gases?

Q. Air is a mixture of many gases, dust particles and water vapour.

Q. Our atmosphere has __% Nitrogen, __ % Oxygen, and __% other gases like carbon dioxide, argon, and water vapour.

Q.

Which of the following will be reduced in air in a city forest when a lot of dust and fly ash is emitted by a coal-based factory in the vicinity?

(a) nitrogen

(b) carbon dioxide

(c) oxygen

(d) water vapour

Q.

Statement I: Air is a mixture of gases, water vapour and dust particles.

Statement II: Air is composed of only one gas that is nitrogen.

Statement III: Air is composed of two gases, nitrogen and oxygen only.

Which of the above statement is incorrect?

Q. A scientist performed experiments to analyse the two samples of air given to him:
'Air Sample A' and 'Air Sample B'. The results of analysis of these two air samples are given below:

Air Sample A				Air Sample B
Oxygen	:	21%		Oxygen	:	16.4%
Carbon dioxide	:	0.04%		Carbon dioxide	:	4.4%
Water vapour	:	A little		Water Vapour	:	A lot

(a) Which air sample, A or B, represents 'exhaled air'? Why?
(b) Which air sample, A or B, represents 'inhaled air'? Why?​