Question

Air is mixture and its compisition keeps on changing from one place to another place justify your answer with help of any two examples

Answer 1

Air is a mixture of many gases and its composition varies from time to time and place to place.  Living organisms breath in oxygen and exhale carbondioxide while plant during photosynthesis release oxygen and take up carbondioxide from the air Examples that air composition varies from place to place are:
1. The concentration of carbondioxide in the atmosphere is about 0.03%.  However it is higher in cities and industrial areas than forests or farmland.  In cities, automobile fumes release gases like carbondioxide and sulphurdioxide into the atmosphere thus increasing their levels in the atmosphere.  In villages which are far off from major cities level of  carbondioxide is closer to its average composition in air. Also, high number of plants in these areas take up carbondioxide from the atmosphere and use it for photosynthesis and release oxygen.  So, oxygen levels in atmosphere are higher in villages.
2. Ozone  is a gas concentrated in the 10- to 50- kilometer height range in the atmosphere just above the stratosphere and its concentration is higher in this layer than trophosphere.