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
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
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.
One of the following factors does not lead to soil formation in nature
  • the Sun
  • water
  • wind
  • polythene bags
The two forms of oxygen found in the atmosphere are
  • water and ozone
  • water and oxygen
  • ozone and oxygen
  • water and carbon dioxide
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
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
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
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
One of the following processes is not a step involved in the water-cycle operating in nature
  • evaporation
  • transpiration
  • precipitation
  • photosynthesis
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
Which of the following is not a greenhouse gas?
  • Methane
  • Carbon dioxide
  • Carbon monoxide
  • Ammonia
Which step is not involved in the carbon-cycle?
  • Photosynthesis
  • Transpiration
  • Respiration
  • Burning of fossil fuels
‘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
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.
Which of the following is a recently originated problem of environment?
  • Ozone layer depletion
  • Greenhouse effect
  • Global warming
  • All of the above
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 CO
  • It is absorbed only by the nasal cells
  • Nitrogen concentration is already more in the cells so it is not at all absorbed.
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.
Choose the correct sequences
  • CO
  • CO2
  • Inorganic carbonates in water organic carbon in plants → organic carbon in animals → scavengers
  • Organic carbon in animals → decomposers → CO
Major source of mineral in soil is the
  • parent rock from which soil is formed
  • plants
  • animals
  • bacteria
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