Page 211 - Science Class 08

i Volcanic eruption, powerful wind, forest fire, decaying of organic matter, etc. are natural
causes of pollution.
i SPM are released by thermal power plants, cement factories, metal industries, etc.

i Chlorofluoro Carbon (CFC) is the main responsible gas for the depletion of ozone layer.
i Acid rain damages crops, plants, buildings, movements, metal structures, soil, etc.
i Water is polluted by the discharge of domestic wastes, industrial effluents, agricultural
wastes into water bodies.

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Exercise
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A. Tick ( ) the correct op on.3
1. Which of the following is not a natural cause of air pollu on?
(a) Volcanic erup on (b) Decaying of organic ma er
(c) Storm (d) Global warming
2. Which of the following gases causes the deple on of ozone layer?
(a) Carbon monoxide (b) Hydrogen chloride

(c) Chlorofluoro carbon (d) Methane
3. Which of the following diseases is not caused by water pollu on?
(a) Asthma (b) Pneumonia
(c) Bronchi s (d) Jaundice

4. Which of the following is caused by water pollu on?
(a) Acid rain (b) Green house effect
(c) Eutrophica on (d) Global warming

B. Fill in the blanks.
1. Ash and smoke released by ___________________ cause air pollu on.
2. Carbon monoxide combines with haemoglobin and reduces its ___________________
carrying capacity.
3. Since CO traps the heat of the atmosphere, the temperature is rising on the earth's
2
surface causing ___________________ .
4. The ___________________ wastes discharged by industries may cause death of animals or
may damage our body organs.
5. ___________________ is an important method of purifying water.
C. Match the following columns.

Column I Column II
1. Thermal power plants a. Carbon dioxide
2. Pes cide b. Algae

3. Green house gas c. Mercury
4. Minamata disease d. Indane
5. Eutrophica on e. SPM

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