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Biology

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Biology

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CBSE Gujarat Board Haryana Board

Previous Year Papers

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Class 10 Class 12

In which one of the following the BOD (Biochemical Oxygen Demand ) of sewage (s), distillery effluent (DE), paper mill effluent (PE) and sugar mill effluent (SE) have been arranged in ascending order?

  • SE < S < PE < DE

  • SE < PE < S < DE

  • PE < S < SE < DE

  • S < DE < PE < SE


D.

S < DE < PE < SE

The ascending order of BOD is sugar mill effulent> paper mill effulent> Distillery effluent> Sewage.

The ascending order of BOD is sugar mill effulent> paper mill effulent> Distillery effluent> Sewage.


Ozone depletion will cause :
  • Forest fire
  • Pneumonia
  • Increased incidence of skin cancer
  • None of these

C.

Increased incidence of skin cancer

In the scrubber in the electrostatic precipitator the gases are passed through :
  • filter
  • lime
  • spray of water
  • both 2 and 3

D.

both 2 and 3

The meaning of BOD is :
  • Bacterial oxygen demand
  • Biological optimum density
  • Biochemical oxygen demand
  • Bioorganisation decay

C.

Biochemical oxygen demand

Which of the following pollutants is not produced by exhaust of motor vehicles ?
  • CO
  • Hydrocarbon
  • Fly-ash
  • NO

C.

Fly-ash

What is the term for the inflammation of cornea due to high absorption of UV-B radiation :
  • myopia
  • snow blindness
  • biomagnification
  • None of the above

B.

snow blindness