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प्रश्न
State what do you understand by the term ‘air’. Explain its importance to mankind.
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उत्तर
Air is a mixture whose composition varies at different intervals of time and different places of the world. Man cannot survive without air and water and hence the air is very essential for survival.
संबंधित प्रश्न
What is meant by ozone depletion?
What is meant by the term ‘atmosphere’? State the role played by the atmosphere for the survival of mankind.
Name the following.
Gases that are harmful to the ozone layer
Answer in your own words.
What are the various constituents of air? Write their uses.
Fill in the blank:
The gas evolved as a product of combustion as well as respiration is ______.
Air has no ______ & ______.
Do sailors need the help of wind to sail?
State whether the following statement is true or false. If false, correct them.
Air does not occupy any space.
Match the items of Column I with the items of Column II
| Column I | Column II | ||
| (a) | Weather cock | (i) | Gases and fine dust particles |
| (b) | Mountaineers | (ii) | Sailing yacht |
| (c) | Fine hair inside the nose | (iii) | Oxygen cylinders |
| (d) | Smoke | (iv) | Direction of air flow |
| (e) | Wind | (v) | Prevent dust particles |
Explain the following observations very briefly
A firki does not rotate in a closed area.
