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10 questions
How much percentage of nitrogen is present in the air?
21%
4%
78%
33%
Which of these causes air pollution?
Throwing litter here and there
Smoke from factories
Both of these
None of these
_________ is the process by which oxygen reacts with a fuel and releases heat energy
Respiration
Oxygen cycle
None of these
Combustion
Moving air is called?
A layer of air called __________ surrounds the earth.
Stratosphere
Troposphere
Atmosphere
_________ is needed for respiration by living things
Water is present in the air in the form of ____________
Water vapor
Water cycle
Carbon-dioxide
Oxygen
The amount of water vapour present in the air is referred as humidity
True
False
Is carbon dioxide important for only animals?
Yes
No
A __________ is an instrument used to show the direction of the wind.
Pin wheel
Wind mill
Wind vane
Fan
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