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4. Warm ocean currents originate from :

(a) poles (b) equator (c) tropics (d) none of these
5. The main cause for ocean currents is :
(a) gravitation (b) rotation of the earth
(c) winds (d) none of these

B. Fill in the blanks :
1. ________________ is a major source of our livelihood.
2. Our earth is called the ________________ planet.
3. The world water day is celebrated annually on ________________.
4. The largest tsunami ever measured was ________________.
5. ________________ of the earth’s surface is covered with water.

C. Match the following :
Column 'A' Column 'B'

1. Waves (a) Form as energy is transferred form molecule to molecute
2. Tide (b) Streams of water moving along definite paths

3. Tsunami (c) Strong seismic waves
4. Ocean currents (d) Periodic rise and fall of water

D. Write ‘T’ for true and ‘F’ for false :
1. The earth appears black from the outer space.

2. The vertical distance from crest to trough is known as the wave height.
3. Low tides help in navigation and fishing too.
4. Ocean water are never still.
5. Water covers about 71% of the earth’s surface.

E. Answer these Questions :
1. What do you know about the distribution of water on the earth’s surface?
2. Define the hydrosphere.
3. Write the importance of the tides in our day to day life.
4. What do you know about the ocean currents? What are the significance of the ocean and their
movements?
5. Define the tides. How are they originated?

Life Skills and Value (Activity)

• Prepare a chart and draw a sketch to show the distribution of water on the earth surface. Paste it
in your scrap book.
• Take a world map and show different oceans of the world. Give different shades to each ocean.
Now, you will see all the oceans are inter connected. There is no boundary between them.

Social Studies-7 27