NCERT Class 9 MCQ Quiz Hub

1. The atmosphere of the Earth is heated by radiations which are mainly
radiated by the Sun
re-radiated by land
re-radiated by water
re-radiated by land and water

2. If there were no atmosphere around the Earth, the temperature of the Earth will
increase
go on decreasing
increase during day and decrease during night
be unaffected

3. What would happen, if all the oxygen present in the environment is converted to ozone?
We will be protected more
It will become poisonous and kill living forms
Ozone is not stable, hence it will be toxic
It will help harmful Sun radiations to reach Earth and damage many life forms.

4. One of the following factors does not lead to soil formation in nature
the Sun
water
wind
polythene bags

5. The two forms of oxygen found in the atmosphere are
water and ozone
water and oxygen
ozone and oxygen
water and carbon dioxide

6. The process of nitrogen-fixation by bacteria does not take place in the presence of
molecular form of hydrogen
elemental form of oxygen
water
elemental form of nitrogen

7. Rainfall patterns depend on
the underground water table
the number of water bodies in an area
the density pattern of human population in an area
the prevailing season in an area

8. Among the given options, which one is not correct for the use of large amount of fertilisers and pesticides?
They are eco-friendly
They turn the fields barren after some time
They adversely affect the useful component from the soil
They destroy the soil fertility

9. The nitrogen molecules present in air can be converted into nitrates and nitrites by
a biological process of nitrogen fixing bacteria present in soil
a biological process of carbon fixing factor present in soil
any of the industries manufacturing nitrogenous compounds
the plants used as cereal crops in field

10. One of the following processes is not a step involved in the water-cycle operating in nature
evaporation
transpiration
precipitation
photosynthesis

11. The term “water-pollution” can be defined in several ways. Which of the following statements does not give the correct definition?
The addition of undesirable substances to water bodies
The removal of desirable substances from water bodies
A change in pressure of the water bodies
A change in temperature of the water bodies

12. Which of the following is not a greenhouse gas?
Methane
Carbon dioxide
Carbon monoxide
Ammonia

13. Which step is not involved in the carbon-cycle?
Photosynthesis
Burning of fossil fuels
Respiration
Burning of fossil fuels

14. ‘Ozone-hole’ means
a large sized hole in the ozone layer
thinning of the ozone layer
small holes scattered in the ozone layer
thickening of ozone in the ozone layer

15. Ozone-layer is getting depleted because of
excessive use of automobiles
excessive formation of industrial Units
excessive use of man-made compounds containing both fluorine and chlorine
excessive deforestation.

16. Which of the following is a recently originated problem of environment?
Ozone layer depletion
Greenhouse effect
Global warming
All of the above

17. When we breathe in air, nitrogen also goes inside along with oxygen. What is the fate of this nitrogen?
It moves along with oxygen into the cells
It comes out with the CO2 during exhalation
It is absorbed only by the nasal cells
Nitrogen concentration is already more in the cells so it is not at all absorbed.

18. Top-soil contains the following
Humus and living organisms only
Humus and soil particles only
Humus, living organisms and plants
Humus, living organisms and soil particles.

19. Choose the correct sequences
CO2 in atmosphere → decomposers → organic carbon in animals → organic carbon in plants
CO2 in atmosphere → organic carbon in plants → organic carbon in animals → inorganic carbon in soil
Inorganic carbonates in water organic carbon in plants → organic carbon in animals → scavengers
Organic carbon in animals → decomposers → CO2 in atmosphere → organic carbon in plants

20. Major source of mineral in soil is the
parent rock from which soil is formed
plants
animals
bacteria

21. Total Earth’s surface covered by water is
75%
60%
85%
50%

22. Biotic component of the biosphere is not constituted by
producers
consumers
decomposer
air

23. An increase in carbon dioxide content in the atmosphere would not cause
more heat to be retained by the environment
increase in photosynthesis in plants
global warming
abundance of desert plants

24. Oxygen is returned to the atmosphere mainly by
burning of fossil fuel
respiration
photosynthesis
fungi

25. Oxygen is returned to the atmosphere mainly by
burning of fossil fuel
respiration
photosynthesis
fungi

26. Low visibility during cold weather is due to
formation of fossil fuel
unbumt carbon particles or hydrocarbons suspended in air
lack of adequate power supply
none of these

27. Growth of lichens on barren rocks is followed by the growth of
moss
ferns
gymnosperms
algae

28. Marked temperature changes in an aquatic environment can affect
breeding of animals
more growth of aquatic plants
process of digestion in animals
availability of nutrients.

29. Soil erosion can be prevented by
raising forests
deforestation
excessive use of fertiliser
overgrazing by animals

30. What happens when rain falls on soil without vegetational cover?
Rain water percolates in soil efficiently
Rain water causes loss of surface soil
Rain water leads to fertility of the soil
Rain water does not cause any change in soil

31. Oxygen is harmful for
ferns
nitrogen fixing bacteria
chara
mango tree