Question

What is the differences between pure air and polluted air ?

• A. Pure air is full of germs and harmful gases while polluted air contains dust particles only.
• B. Pure air contains harmful gases while polluted air contains very few harmful gases.
• C. Pure air is free from germs and harmful gases while polluted air contains harmful gases and unwanted substances.
• D. Pure air is free from germs and harmful gases but it contains lot of dust particles.

Answer 1

The correct option is C Pure air is free from germs and harmful gases while polluted air contains harmful gases and unwanted substances.

Pure air contains around 78% nitrogen, 21% oxygen and 0.03% carbon dioxide. It is fresh and healthy for lungs. Polluted air has no such definite composition of these gases and can cause respiratory problems.