(a) What do the blanks 1, 2, 3, 4 and 5 in the given cycle stand for ? (b) Name two natural and one man-made process - by which CO2 returns to the atmosphere. (c) Carbon dioxide is necessary for plants but it is also a pollutant, justify your answer

CBSE Class 9 CBSE Class 9 Science
1

(a) What do the blanks 1, 2, 3, 4 and 5 in the given cycle stand for ?
(b) Name two natural and one man-made process - by which CO2 returns to the atmosphere.
© Carbon dioxide is necessary for plants but it is also a pollutant, justify your answer.

2

(a) 1 - Organic compounds (plants)
2 - Organic compounds (animals)
3 - Inorganic carbonates (shells)
4 - Carbonates in water
5 - limestone
(b) Respiration.
Decomposition.
Combustion of fuel.
© (i) CO2 causes the average temperature to increase.
(ii) CO2 is responsible for global wanning.