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प्रश्न
Tick (√) the most appropriate answer.
The humans pollute the air by :
पर्याय
burning a vast amount of coal
burning waste materials
using petrol and diesel vehicles
all the above
उत्तर
all the above
APPEARS IN
संबंधित प्रश्न
Write ‘True’ or ‘False’ in front of following statement.
The catalyst used in laboratory preparation of oxygen gas from hydrogen peroxide gas is magnesium oxide
Give reason:
When water is heated, we see bubbles rising up.
You are given a test tube with two outlets and a bottle of lime water. Using same, how would you demonstrate experimentally the presence of carbon dioxide in air.
What happens if the percentage of carbon-dioxide increases in the air?
______ is the percentage of nitrogen in air.
How do astronauts breathe when they go beyond the earth’s atmosphere?
All living things use oxygen for breathing.
What is the presence of harmful substance in the air called?
______ gas cylinders are used for breathing purpose for a diver going deep into the sea.
Boojho took an empty plastic bottle, turned it upside down, and dipped its open mouth into a bucket filled with water. He then tilted the bottle slightly and made the following observations.
(i) Bubbles of air came out from the bottle.
(ii) Some water entered the bottle.
(iii) Nitrogen gas came out in the form of bubbles and oxygen got dissolved in water.
(iv) No bubbles formed, only water entered the bottle.
Which observations is/are correct?
