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Warm currents raise the temperature over land surface while cold currents decrease the
temperature of the coastal areas. In places where warm and cold current meet, dense fog is
produced which reduces the visibility. These areas are also the best fishing ground in the world.
Planktons which are an excellent source of food for fishes are found here in abundance.
Major Ocean Currents
Now I Know :
The earth is a watery planet. 71% of its surface is covered with water which is found in oceans, seas, rivers, lakes, etc.
The hydrological cycle describes the movement of water on, in and above the earth surface.
Waves form as energy is transferred from molecule to molecule across the surface.
Ocean waters are never still. Waves, tides and currents are its main movement.
The two types of sources of water are surface water and ground water.
Horizontal Movement of ocean water in the form of streams in a definite direction is called ocean current.
(Assessment of Learning Outcome)
A. Tick () the correct option :
1. Which one of the following contains the maximum amount of water found on the earth’s surface?
(a) Sea (b) Lakes (c) Oceans (d) Bays
2. The domains of water is called the :
(a) biosphere (b) hydrosphere (c) cycosphere (d) none of these
3. Which of the following are responsible for the origin of tides?
(a) Gravitational pull of the moon (b) Gravitational pull of the sun
(c) Gravitational pull of the earth (d) Both (a) and (b)
Social Studies-7-7
26 Social Studies
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