Page 2 - CBW

6. Assertion (A): Plants help maintain the balance of oxygen and carbon dioxide in the air.
Reason (R): Plants take in oxygen and release carbon dioxide during photosynthesis.
7. Assertion (A): Air pollution is only caused by factories.
Reason (R): Vehicles and burning of fuels also cause air pollution.

8. Study the picture and answer the following questions:

a) Identify the natural cycle illustrated here.
b) Define it.
c) Name the gases that are exchanged here.
d) What are the two major processes involved in
production of the above-mentioned gases?

9. Air is not only required in respiration and photosynthesis, but is used in number of ways. Air
helps in dispersal of seeds, generate electricity through wind mills.
Question:
a) Explain how air contributes to the dispersal of seeds in plants?
b) How air plays an important role in the water cycle?
c) Give one more use of air apart from discussed above.

10. In a city, the air quality has deteriorated due to increased vehicular emissions and industrial
activities. Residents have reported:
I. Increased respiratory problems.
II. Reduced visibility due to smog.
III. Damage to plants and buildings.

Questions:
1. Which gas is primarily responsible for smog formation?
2. What health issues can arise from poor air quality?
3. What is one measure to improve air quality?

11. In the picture, a policeman is wearing a mask while
regulating traffic.

Questions:

a) Why is the policeman wearing a mask?
b) What does this indicate about the quality of air in
crowded areas?
c) How can wearing a mask protect individuals in such
environments?