Page 143 - SST Class 07

A. Tick (3) the correct option.

1. The gas which is important for growth of plants is :
(a) Ozone (b) Oxygen (c) Carbon dioxide

2. The layer of atmosphere which is cloud-free is :
(a) Mesosphere (b) Stratosphere (c) Exosphere
3. A wind vane is used to see:
(a) wind direction (b) wind speed (c) wind pressure

4. Main source of groundwater is :
(a) river water (b) rain water (c) ocean water

5. The temperature at which air gets saturated is :
(a) dew point (b) condensation point (c) humidity point

B. Fill in the blanks.

1. The radius of the earth is roughly about __________________ .
2. The earth’s atmosphere has __________________ main layers.
3. __________________ level in the atmosphere, affects the earth’s weather and climate.

4. __________________ layer extends upto a height of 80 kms.
5. The movement of air is always from areas of __________________ pressure to areas of
__________________ pressure.
6. Weather pattern of more than __________________ is considered for defining the climate
of a place.
7. Wind direction is measured by an instrument known as the __________________ .

C. Give reasons for the following.
1. Why don’t we feel air pressure?
2. Why does the amount of insolation differ from tropical belt to polar regions?

D. Distinguish between the following.
1. Troposphere and Stratosphere

2. Weather and Climate
E. Answer the following questions.

1. Describe the structures of the atmosphere.
2. What are the factors affecting temperature of a place?
3. Briefly describe the different types of winds.

4. What are the different types of rainfalls?

Social Science-7 143