CBSE Questions for Class 12 Medical Biology Environmental Issues Quiz 2 - MCQExams.com

Deforestation will decrease
  • Soil erosion
  • Land slides
  • Soil fertility
  • Rainfall
Main cause of extinction of species from tropical areas is
  • Afforestation
  • Deforestation
  • Pollution
  • Soil erosion
Eutrophication is excess growth of
  • Bryophytes
  • Algae and aquatic plants
  • Gymnosperms
  • Pteridophytes
Decrease in species diversity in tropical countries is mainly due to
  • Urbanisation
  • Pollution
  • Deforestation
  • Soil erosion
Eroded soils are
  • Devoid of plant nutrients
  • Richer in plant nutrients
  • Unaltered in plant nutrients
  • Fit for agriculture
Global warming will cause.
  • Rise is level of oceans
  • Decrease in glaciers
  • Reduction in ice caps
  • All the above
Deforestation generally decreases
  • Global warming
  • Drought
  • Rainfall
  • Soil erosion
Atomic bomb was used during World War II in.
  • $$1941$$
  • $$1939$$
  • $$1943$$
  • $$1945$$
The first atomic bomb was thrown over.
  • Nagasaki
  • Hiroshima
  • Tokyo
  • Hong Kong
Biochemical oxygen demand measures
  • Industrial pollution
  • Air pollution
  • Dissolved oxygen required for decomposers
  • Pollution capacity of effluents
Global Warming Clauses 
I. An increase in the sea level
II. The melting of ice at mountain peaks
III. A decrease in food production by plants
  • I only
  • I and II
  • II and III
  • I,II and III
Which one of the following is a greenhouse gas?
  • Oxygen
  • Methane
  • Sulphur dioxide
  • Nitrogen
Statement 1 : BOD represents the amount of dissolved oxygen that would be consumed if all the organic matter in one litre of water were oxidised by microorganisms.
Statement 2 : High value of BOD indicates that water is highly polluted by organic matter.
  • Both statements 1 and 2 are correct.
  • Statement 1 is correct but statement 2 is incorrect.
  • Statement 1 is incorrect but statement 2 is correct.
  • Both statements 1 and 2 are incorrect.
Bag filters are used for removal of pollutants from
  • Exhaust emissions
  • Effluent water
  • Sewage water
  • Both B and C
Read the following statements carefully.
(i) An electrostatic precipitator removes particulate matter by imposing negative charge on them.
(ii) Catalytic converters convert unburnt hydrocarbons into $$ { CO }_{ 2 } $$ and water.
(iii) Peroxyacyl nitrates (PAN) is a secondary pollutant.
(iv) DDT is a non-biodegradable pollutant.

Which of the above statements are incorrect ?
  • (i) and (ii)
  • (iii) and (iv)
  • (i) and (iii)
  • None of these
Match column I with column II and select the correct option from the given codes.
Column IColumn II
A.Electrostatic precipitator(i)Removes gases like $$SO_2$$
B.Scrubber(ii)Reduces automobile emission
C.Catalytic converter(iii)Removes particulate matter
  • A - (ii), B - (iii), C - (i)
  • A - (iii), B - (ii), C - (i)
  • A - (i), B - (ii), C - (iii)
  • A - (iii), B - (i), C - (ii)
Given below is a diagram of electrostatic precipitator. Identify A, B, C and D and select the correct option.
929332_f18c83bf90994e2a928f644de6c2abc0.png
  • A- Negatively charged wire, B- Negatively charged dust particles, C- Discharge corona, D- collection
  • A- Negatively charged wire, B- Discharge corona, C- Collection plate, D- Negatively charged dust particles
  • A- Positively charged wire, B- Positively charged dust particles, C- Discharge corona, D- Collection plate
  • A-Positively charged wire, B- Discharge corona, C- Collection plate, D- Positively charged dust particles
Eutrophication is often seen in
  • Oceans
  • Mountains
  • Deserts
  • Fresh water lakes
Air pollution management for particulate matter is carried out by devices such as arresters. The device which is not an example of arrester is:
  • Cyclonic seperator
  • Scrubber seperator
  • Gravity settling chamber
  • Teflon porous bags or filters
Which of the following actions can be taken to control noise pollution ?
  • Delimitation of horn-free zone around hospitals and schools
  • Permissible sound-levels of crackers and of loudspeakers
  • set the timing after which loudspeakers cannot be played
  • All of these
A pollution control device which can remove gases like $$SO_2$$ are known as
  • Electrostatic precipitator
  • Scrubber
  • Chimneys
  • Both A and B
Organic farming includes :
  • Use of fertilisers and pesticides of biological origin
  • IPM (Integrated Pest Management)
  • Locally developed pest resistant varieties
  • All of these
Which one of the following is the correct percentage of (the two out of four) greenhouse gases that contribute to the total global warming?
  • N$$_2$$O 6%, CO$$_2$$ 86%
  • Methane 20%, N$$_2$$O 18%
  • CFC 14%, Methane 20%
  • CO$$_2$$ 40%, CFC 30%
Why is the concentration of ozone less over the north and south poles?
  • CFC's accumulate only in area where the air is cold.
  • CFC use is highest in these areas.
  • CFC's stick to frozen water vapour and are able to act as catalysts.
  • UV rays are stronger in the atmosphere.
Gaseous pollutants can be controlled by
  • Electrostatic precipitators
  • Pyrolysis
  • Incineration
  • Adsorption
  • None of the above
Which of the following strategy is not a correct approach to reduce global warming?
  • Reducing the green house gas emission by limiting the use of fossil fuels.
  • Increase the vegetation cover, particularly the forest for photosynthetic utilization of $$CO_2$$.
  • Minimizing the use of nitrogen fertilizers in agriculture for reducing $$N_2$$O emission.
  • Increasing the use of air conditioners, refrigeration unit and production of plastic foams and propellants in aerosal spray cans.
  • Developing substitutes for chlorofluorocarbons.
Steps taken by the government of India to control air pollution include
  • Compulsory mixing of 20% ethyl alcohol with petrol and 20% biodiesel with diesel.
  • Compulsory PUC (Pollution Under Control) certification of petrol driven vehicles which tests for carbon monoxide and hydrocarbons.
  • Permission to use only pure diesel with a maximum of 500 ppm sulphur as fuel for vehicles.
  • Use of non - polluting compressed Natural Gas (CNG) only as fuel by all buses and trucks.
If global warming continues, the organism which may face more severe threat is
  • Cow
  • Lion
  • Snow leopard
  • Dolphin
Freon gas causing stratospheric $$O_{3}$$ depletion is mainly released from
  • Refrigerator
  • Automobile
  • Thermal power plant
  • Steel industry
Good ozone is found in 
  • Atmosphere
  • Biosphere
  • Stratosphere
  • Ozonosphere
Protective layer of ozone in the atmosphere exists in which layer?
  • Troposphere
  • Lonosphere
  • Stratosphere
  • Atmosphere
Biochemical Oxygen Demand (BOD) in a river water
  • Remains unchanged when algal bloom occurs
  • Has no relationship with concentration of oxygen in the water
  • Gives a measure of salmonella in the water
  • Increases when sewage gets mixed with river water
Limit of BOD prescribed by Central Pollution Control Board, for the discharge of industrial and municipal waste waters into the surface water is:
  • < 100 ppm
  • < 30 ppm
  • < 3.0 ppm
  • < 10 ppm
BOD stands for
  • Biological organism death
  • Biochemical organic matter decay
  • Biotic oxidation demand
  • Biochemical oxygen demand
The pollution in city like Delhi may be controlled to great extent
  • By proper sewage and proper exit of chemicals from factories
  • By wide roads and factories away from the city
  • By cleaning city and scanty use of pesticides
  • All of the above
Phosphorus-32 emits
  • $$\alpha$$ particles
  • $$\beta$$ particles
  • $$\gamma$$ particles
  • X-rays
Which one of the following chemicals is responsible for the reduction of ozone content of atmosphere?
  • Hydrochloric acid
  • Photochemical smog
  • Chlorofluorocarbon (CFC)
  • Sulphur dioxide
What are the chief pollutants of the atmosphere, which are most likely to deplete the ozone layer?
  • Sulphur dioxide
  • Nitrogen oxide and Fluorocarbons
  • Carbon dioxide
  • Carbon monoxide
Measurement of the rate of oxygen consumption in unit volume of water over a period of time is done to find out
  • Biogas generation
  • Biological oxygen demand
  • Biosynthetic pathways
  • Fermentation
Increase in the percentage of fauna and decrease in flora may be dangerous because it enhances
  • Percentage of $$CO_2$$
  • Percentage of radioactive fallout
  • Percentage of $$O_2$$
  • Percentage of diseases
The purpose of biological treatment of waste-water is to
  • Reduce BOD
  • Increase BOD
  • Reduce sedimentation
  • Increase sedimentation
Fishes die by sewage because  
  • Of its bad smell.
  • It replaces food material of fishes.
  • It increases oxygen competition among fishes.
  • $$CO_2$$ is mixed in large amount in water.
CFC are not recommended to be used in refrigerators because they
  • Increase temperature
  • Deplete ozone
  • Affect environment
  • Affect human body
When huge amount of sewage is dumped into a river, the BOD will
  • Increase
  • Remain unchanged
  • Slightly decrease
  • Decrease
Gases referred to as 'green house gases' are
  • CO$$_2$$, O$$_2$$, NO$$_2$$, NH$$_3$$
  • Chlorofluoro carbon, CO$$_2$$, NH$$_3$$, N$$_2$$
  • CH$$_4$$, N$$_2$$, CO$$_2$$, NH$$_3$$
  • Chlorofluoro carbon, CO$$_2$$, CH$$_4$$, NO$$_2$$
A lake with an inflow of domestic sewage rich in organic waste may result in:
  • Drying of the lake very soon due to algal bloom.
  • An increased production of fish due to lot of nutrients.
  • Death of fish due to lack of oxygen.
  • Increased population of aquatic food web organisms.
Greenhouse effect refers to 
  • Cooling of Earth
  • Trapping of UV rays
  • Production of cereals
  • Warming of Earth
Which of the following does not occur when the sewage is discharged into water?
  • Increase in $$O_2$$
  • Cyanophycean blooms occur
  • Depletion of $$O_2$$ layers
  • Eutrophication
In coming years, skin related disorders will be more common due to:
  • Pollutants in air
  • Use of detergents
  • Water pollution
  • Depletion of ozone layer
The most adverse effect of radioactive pollutant is
  • Gene mutation
  • Hepatitis
  • Polio
  • T.B.
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Practice Class 12 Medical Biology Quiz Questions and Answers