1. Which gas has highest percentage in air

a. O2
b. CO2
c. N2
d. O2

2. Lowest temperature in stratosphere is

a. -5^oC
b. -55^oC
c. 5^oC
d. 55^oC

3. Which is responsible for acid rain

a. SO2
b. NO2
c. both NO2 and SO2
d. O3

4. Which is reddish brown gas

a. NO
b. NO2
c. SO2
d. O3

5. Troposphere extends upto

a. 50km
b. 12km
c. 80km
d. 18km

6. Stratosphere extends upto

a. 50km
b. 12km
c. 18km
d. 80km

7. Ozone layer is found in

a. troposphere
b. stratosphere
c. mesosphere
d. thermosphere

8. Most air pollution is caused by

a. ozone
b. acid rain
c. carbon monoxide
d. burning of fossil fuels

9. Which layer is closest to earth

a. stratosphere
b. thermosphere
c. troposphere
d. mesosphere

10. Outermost layer of earth atmosphere is

a. mesosphere
b. startosphere
c. troposphere
d. thermosphere