Our Environment MCQ with Solution
1.  Which one of the following is the definition of ecosystem ?
(A) A localised association of seven plants and animals
(B) Different communities of plants, animals and microbes, together with their physicochemical environments
(C) Different communities of plants and microbes, plus their physicochemical environments
(D) A community of organisms interacting with one another
Ans.    (B)
Sol.     Different communities of plants, animals and microbes together with their physicochemical environment is included in ecosystem.
2.  The study of interrelationship between living organisms and their environment is called
(A) Phytogeography
(B) Ecology
(C) Phytosociology
(D) Ecosystem
Ans.    (B)
Sol.     The study of interrelationship between living organisms and their environment is called Ecology.
3.  Primary source of energy in an ecosystem is
(A) Sugar stored in plants
(B) Heat liberated during respiration
(C) Solar energy
(D) Heat liberated during fermentation
Ans.    (C)
Sol.     Primary source of energy in an ecosystem is solar energy which is trapped by green plants.
4. Good soil is
(A) Which allows the limited amount of water into it
(B) Which allows water to percolate slowly
(C) Which allows to pass water very quickly from it
(D) Which holds whole of water into it
Ans.    (B)
Sol.     Good soil is that which allows water to percolate slowly so this water can be used by plants.
5. The least porous soil among the following is
(A) Clay soil
(B) Sandy soil
(C) Peaty soil
(D) Loam soil
Ans.    (A)
Sol.     The least porous soil among the following is Clay soil. This soil has less air holding capacity and more water holding capacity.
6. The layer of air that absorbs harmful sun rays is :
(A) Troposphere
(B) Ozonosphere
(C)Â Stratosphere
(D) Ionosphere
Ans.    (B)
Sol.     The layer of air that absorbs harmful sun rays is Ozonosphere.
7. Plants utilize :
(A) Capillary water
(B) Hygroscopic water
(C) Gravitational water
(D) Water by holding
Ans.    (A)
Sol.     Plants utilize capillary water. Capillary water is present between soil particles.
8. Most plants are green in colour because :
(A) The atmosphere filter out all the colours of the visible light spectrum except green.
(B) Green light is the most effective wavelength region of the visible spectrum for photosynthesis
(C) Chlorophyll is least effective in absorbing green light
(D) Green light allows maximum photosynthesis
Ans.    (C)
Sol.     Chlorophyll reflects green light while absorbs maximum light of VIBGYOR so plants are green in colour.
9. Sedimentary cycle having components :
(A) Phosphorus
(B) Sulphur
(C) Both (A) and (B)
(D) Carbon
Ans.    (C)
Sol.     Materials involved in circulation between biotic and abiotic components of biosphere are nongaseous and the reservoir pool is lithosphere. This biogeochemcial cycle is known as Sedimentary cycle
10. The two components of an ecosystem are .
(A) Plants and animals
(B) Weeds trees animals and man
(C) Energy flow and mineral cycling
(D) Biotic and abiotic
Ans.    (D)
Sol.     Living components of an ecosystem include producers, consumers and decomposers. A non living components include abiotic components like air, water, rainfall and soil.
11. A fertile soil is likely to have a pH value of :
(A) 3-4
(B) 8-9
(C) 6-7
(D) 10-11
Ans.    (C)
Sol.     A fertile soil is likely to have a pH value of 6-7.
12. An aquatic plant with floating leaves :
(A) Have stomata on leaf surface
(B) Have stomata on lower surface
(C) Do not have stomata
(D) Have stomata
Ans.    (A)
Sol.     An aquatic plant with floating leaves have stomata on upper surface and such leaves are called epistomatous.
13. Which of the following is a logical sequence in carbon cycle?
(A) Producer-consumer-decomposer
(B) Decomposer-consumer-producer
(C) Producer-decomposer-consumer
(D) Consumer-producer-decomposer
Ans.    (A)
Sol.     Producer-consumer-decomposer.
14. The leguminous plants are important in agriculture because :
(A) They need very little water to grow
(B) They are disease resistant
(C) They help in nitrogen economy of the plants
(D) Six crops of leguminous plants are harvested in a year
Ans.    (C)
Sol.     The leguminous plants are important in agriculture because They help in nitrogen economy of the plants.
15. To prevent soil erosion, a farmer plants a hedge across a field. This method works because :
(A) The hedge prevents the soil from direct impact of rainwater
(B) The roots of plants prevent the soil erosion
(C) The hedge absorbs minerals from the soil, which makes it most compact
(D) None of the above
Ans.    (B)
Sol.     To prevent soil erosion, a farmer plants a hedge across a field. This method works because the roots of plants prevent the soil erosion.
16.  If there was no carbon dioxide in the earth’s atmosphere, the temperature of the earth would be :
(A) Higher than the present
(B) Dependent on the amount of oxygen in the atmosphere
(C) Less than the present
(D) The same
Ans.    (C)
Sol.     If there was no carbon dioxide in the earth’s atmosphere, the temperature of the earth would be Less than the present. Hence CO2 is green house gas which increases temperature.
17. The plants growing in a particular area are related with :
(A) Other plants of that region
(B) Soil of the region
(C) Available light
(D) All of the above
Ans.    (D)
Sol.     The plants growing in a particular area are related with other plants of that region, soil of the region, Available light.
18. True xerophytes have :
(A) Lower rate of transpiration than mesophytes
(B) Transpiration rate equal to mesophytes
(C) Transpiration rate higher than mesophytes
(D) No transpiration
Ans.    (A)
Sol.     True xerophytes have lower rate of transpiration than mesophytes.
19. Which of the following environments is richest in free oxygen :
(A) Warm fresh water
(B) Atmosphere
(C) Cold fresh water
(D) Salt water
Ans.    (B)
Sol.     Atmosphere is richest in free oxygen.
20. Blue baby syndrome is due to–
(A) Mercury poisoning
(B) Higher concentration of nitrate in drinking water
(C) O3
(D) CH4
Ans.    (B)
Sol.     Blue baby syndrome is due to higher concentration of nitrate in drinking water.
21. The food chain that starts from plants and goes from smaller to larger animals is
(A) Predator food chain
(B) Saprophytic food chain
(C) Detritus food chain
(D) Parasitic food chain
Ans.    (A)
Sol.     The food chain that starts from plants and goes from smaller to larger animals is predator food chain.
22.  When a big fish eats a small fish, which eats water fleas supported by phytoplankton, the water fleas are
(A) Primary consumers
(B) Secondary consumers
(C) Top consumer in this food chain
(D) Producers
Ans.    (A)
Sol.     When a big fish eats a small fish, which eats water fleas supported by phytoplankton, the water fleas are Primary consumers
23. A crocodile had just eaten a lamb when a hawk saw the crocodile, attacked it and consumed it. The hawk is in ecological terms
(A) A producer
(B) A primary consumer
(C) A secondary consumer
(D) A tertiary consumer
Ans.    (D)
Sol.     A crocodile had just eaten a lamb when a hawk saw the crocodile, attacked it and consumed it. The hawk is a tertiary consumer.
24. In natural ecosystem, decomposers include
(A) Only microscopic animals
(B) Only bacteria and fungi
(C) The above two types of organisms plus microscopic animals
(D) Â None of the above
Ans.    (B)
Sol.     In natural ecosystem, decomposers include bacteria and fungi.
25. The food chain in which microorganisms break down the energy rich compounds synthesized by producers is :
(A) Detritus food chain
(B) Predator food chain
(C) Consumer food chain
(D) Parasitic food chain
Ans.    (A)
Sol.     The food chain in which microorganisms break down the energy rich compounds synthesized by producers is detritus food chain.
26. Driving force of ecosystem is
(A) Carbohydrate in plants
(B) Biomass
(C) Solar energy
(D) Producer
Ans.    (C)
Sol.     Driving force of ecosystem is solar energy.
27. The pyramid of biomass is inverted in
(A) Pond ecosystem
(B) Grassland ecosystem
(C) Forest ecosystem
(D) All the above
Ans.    (A)
Sol.     The pyramid of biomass is inverted in pond ecosystem.
28. Which of the following is upright in all the ecosystems ?
(A) Pyramid of number
(B) Pyramid of energy
(C) Pyramid of biomass
(D) All the above
Ans.    (B)
Sol.     Pyramid of energy is upright in all the ecosystems.
29. In nitrogen cycle the bacteria, which change proteins to ammonia, are known as
(A) Bacteria of decay
(B) Denitrifying bacteria
(C) Nitrogen fixing bacteria
(D) Nitrate bacteria
Ans.    (A)
Sol.     In nitrogen cycle the bacteria, which change proteins to ammonia, are known as bacteria of decay.
30. The denitrification means
(A) Reduction of NO2Â to ammonia by bacteria in the soil
(B) Conversion of ammonia to amino acids
(C) Conversion of ammonia and nitrates to gaseous nitrogen
(D) Oxidation of ammonia to nitrate
Ans.    (C)
Sol.     The denitrification means conversion of ammonia and nitrates to gaseous nitrogen.
31. Detritus food chain begins with :
(A) Producer                                                  Â
(B) Carnivores                                                Â
(C) Dead Organism                                        Â
(D) DecomposerÂ
Ans.    (C)
Sol.     Detritus food chain begins with dead organism.
32. In the terrestrial ecosystem, minimum energy is present in :
(A) T1Â Â Â
(B) T2Â Â Â
(C) T4Â Â Â
(D) T3Â
Ans.    (C)
Sol.     In the terrestrial ecosystem, minimum energy is present in T4 .
33. In pyramid of food, the producers occupy :
(A) The base                                                  Â
(B) Position near the base
(C) Apex                                                        Â
(D) Position near apex
Ans.    (A)
Sol.     In pyramid of food, the producers occupy the base.
34. Total organic matter present in an ecosystem is called :
(A) Biome                                                      Â
(B) Biomass                                                   Â
(C) Litter                                                        Â
(D) FoodÂ
Ans.    (B)
Sol.     Total organic matter present in an ecosystem is called Biomass .
35. The number of individuals of a species in a particular ecosystem of a given time remains constant due to :
(A) Human beings                                          Â
(B) Parasites                                                 Â
(C) Predators                                                 Â
(D) Food availability
Ans.    (C)
Sol.     The number of individuals of a species in a particular ecosystem of a given time remains constant due to predators. Predators depend upon the herbivores.
36. Community is :
(A) Group of independent and interacting populations of same species
(B) Group of independent and interacting populations of same species in specific area.
(C) Group of independent and interacting populations of different species in an area
(D) Group of independent and interacting populations of different speciesÂ
Ans.    (C)
Sol.     Community is group of independent and interacting populations of different species in an area.
37. Biome is :
(A) Sum of ecosystems in a geographical area
(B) Sum of ecosystems of whole earth
(C) Biotic components of an ecosystem
(D) Biotic potential of a populationÂ
Ans.    (A)
Sol.     Biome is sum of ecosystems in a geographical area.
38. Egret bird on the back of the buffalo eating lice is an example of :
(A) Commensalism                                        Â
(B) Mutualism                                                 Â
(C) Parasitism                                               Â
(D) ScavengingÂ
Ans.    (B)
Sol.     Egret bird on the back of the buffalo eating lice is an example of Mutualism .
39. When animals feed on other dead animals, which had died naturally or had been killed by another animals, the relationship is termed as :
(A) Predation                                                 Â
(B) Competetion
(C) Scavenging                                              Â
(D) Symbiosis
Ans.    (C)
Sol.     When animals feed on other dead animals, which had died naturally or had been killed by another animals, the relationship is termed as scavenging.
40. Which of the following is the correct sequence in food chain :
(A) Fallen leaves → bacteria → insect larvae → birds
(B) Phytoplankton → zooplankton → fish
(C) Grasses → fox → rabbit
(D) Grasses → chameleon → insect → birds
Ans.    (B)
Sol.     Phytoplankton → zooplankton → fish
41. The presence of ozone in the atmosphere of earth
(A) Is advantageous since it supplies O2Â for people travelling in jets
 (B) Helps in checking the penetration of ultraviolet rays to earth
(C) Hinder higher rate of photosynthesis          Â
(D) Has been responsible for increasing the average global temperature in recent years
Ans.    (B)
Sol.     The presence of ozone in the atmosphere of earth helps in checking the penetration of ultraviolet rays to earth.
42. Lichens are important in the studies on atmospheric pollution because they
(A) Can also grow in greatly polluted atmosphere                                                       Â
(B) Can readily multiply in polluted atmosphere
(C) Are very sensitive to pollutants like SO2Â Â Â Â Â Â
(D) Efficiently purify the atmosphere
Ans.    (C)
Sol.     Lichens are important in the studies on atmospheric pollution because they are very sensitive to pollutants like SO2
43. Geothermal energy is :
(A) Nonrenewable non-conventional energy source                                                     Â
(B) Nonrenewable conventional energy source
(C) Renewable non conventional energy source
(D) Renewable conventional energy source
Ans.    (C)
Sol.     Geothermal energy is renewable non conventional energy source.
44. Biomagnification is the phenomenon of –
(A) Culturing fungi in waste material for gain in protein rich biomass
(B) Cultivation of fast growing trees to increase wood production
(C) Increased nitrogen fixation by a combined growth of blue–green algae and nitrogen fixing bacteria
(D) Increase in the concentration of non biodegradable substances with passage through food chain within the body of organisms.
Ans.    (D)
Sol.     Biomagnification is the phenomenon of increase in the concentration of non biodegradable substances passing through food chain within the body of organisms.
45. DDT is
(A) Non-Biodegradable pollutant                     Â
(B) Degradable pollutant
(C) Green house gas                                      Â
(D) None of these
Ans.    (A)
Sol.     DDT is Non-Biodegradable pollutant.
46. Terracing is an effective method of soil conservation in
(A) Desert areas                                             Â
(B) Plain areas                                               Â
(C) Hill areas                                                  Â
(D) None of these
Ans.    (C)
Sol.     Terracing is an effective method of soil conservation in hilly areas.
47. Which of the following is an inexhaustible natural resource.
(A) Fossil fuels                                              Â
(B) Minerals                                                   Â
(C) Atomic power                                          Â
(D) ForestÂ
Ans.    (C)
Sol.     Atomic power is an inexhaustible natural resource.
48. Flow of water along the slopes can be controlled by :
(A) Contour bunding                                       Â
(B) Gully plugging                                          Â
(C) Ridging the land                                      Â
(D) Stub growing
Ans.    (A)
Sol.     Flow of water along the slopes can be controlled by contour bunding.
49. E.coli is used as an indicator organism to determine pollution of water with :
(A) Industrial effluents                                    Â
(B) Heavy metals
(C) Pollen of aquatic plants                            Â
(D)Â Faecal matter
Ans.    (D)
Sol.     E. coli is used as an indicator organism to determine pollution of water with faecal matter.
50. Itai-itai is caused due to :
(A) Mercury                                                    Â
(B) Lead                                                        Â
(C) Cadmium                                                 Â
(D) Copper
Ans.    (C)
Sol.     Itai-itai is caused due to Cadmium.
51. Biomagnification is shown by :
(A) Nondegradable pesticides                        Â
(B) Degradable pesticides
(C) Domestic wastes                                     Â
(D) Weedicides
Ans.    (A)
Sol.     Biomagnification is shown by nondegradable pesticides.
52. Fluoride pollution mainly affects :
(A) Brain                                                       Â
(B) Heart
(C) Teeth                                                       Â
(D) Kidney
Ans.    (C)
Sol.     Fluoride pollution mainly affects teeth.
53. Entry of sewage in water caused a spurt in the growth of algae but killed fish due to –
(A) Decrease in nutrients                                Â
(B) Reduction in light
(C) Depletion of oxygen                                Â
(D) All of the above
Ans.    (C)
Sol.     Entry of sewage in water causes a spurt in the growth of algae but kills fish due to depletion of oxygen.
54. Water is after treated with chlorine to :
(A) Increase oxygen contents                         Â
(B) Kill germs
(C) Remove hardness                                    Â
(D) Remove suspended particles
Ans.    (B)
Sol.     Water is after treated with chlorine to kill germs.
55. Corrosion of statues and monuments occurs due to :
(A) Photochemical smog                               Â
(B) COÂ
(C) Acid rain                                                  Â
(D) Methane
Ans.    (C)
Sol.     Corrosion of statues and monuments occurs due to acid rain.
56. Which one of the following is not a greenhouse gas :
(A) CO2Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
(B) CH4Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
(C) O2Â Â
(D) CFC’s
Ans.    (C)
Sol.     O2  is not a greenhouse gas.
57. Pollutant released by jet planes is :
(A) Fog
(B) Aerosol                                                   Â
(C) Smog                                                      Â
(D) Colloid
Ans.    (B)
Sol.     Pollutant released by jet planes is Aerosol.
58. Ozone depletion in stratosphere would result in :
(A) Forest fires                                              Â
(B) Increased incidence of skin cancer
(C) Global warming                                        Â
(D) None of the above                                   Â
Ans.    (B)
Sol.     Ozone depletion in Stratosphere would result in increased incidence of skin cancer.
59. Ozone blanket is present in which of the following main layers of atmosphere ?
(A) Mesosphere                                            Â
(B) Troposphere                                            Â
(C) Stratosphere                                            Â
(D)Â Thermosphere
Ans.    (C)
Sol.     Ozone blanket is present in Stratosphere.
60. Which of the following is an exhaustible natural resource :
(A) Solar radiation                                         Â
(B) Air Â
(C) Minerals                                                  Â
(D) Water
Ans.    (C)
Sol.     Minerals are an exhaustible natural resource because these are exhausted after some time.
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