Q1. Answer the following questions briefly.
I) why do the plates move?
Ans. The plates move because of the movement of the molten magma inside the earth.
Ii) what are exogenic and endogenic forces?
- Exogenic forces- the forces that act on the surface of the earth are called as exogenic forces.
- Endogenic forces- the forces that act in the interior of the earth are called as endogenic forces.
Iii) what is erosion?
Ans. Erosion is the wearing away of the landscape by different agents like air, water and ice.
Iv) how are flood plains formed?
Ans. During floods, layers of the fine soil and other material called sediments are deposited on the river banks. This leads to the formation of a flat and fertile flood plain.
V) what are sand dunes?
Ans. Sand dunes are low hill like structures formed by the deposition of sand in a desert.
Vi) how are breaches formed?
Ans. Breaches are formed when the sea waves deposit sediments along the shores of the sea.
Vii) what is ox bow lake?
Ans. When the meander loop is cut-off from the main river, it forms a cut-off lake. As its shape is like an ox bow hence it is called ox bow lake.
Q2. Tick the correct answer.
I) which is not an erosional feature of sea waves?
C) sea wave
Ii) the depositional feature of a glacier is-
A) flood plain
Iii) which is caused by the sudden movement of the earth?
C) flood plain
Iv) mushroom rocks are found in-
B) river valleys
V) ox bow lakes are found in-
b) river valleys
Q3. Match the followings.
Glacier – river of ice
Meanders – hard bed rocks
Beach – seashore
Sand dunes – deserts
Waterfall – rivers
Earthquakes – vibrations of earth
Q4. Give reasons.
I) some rocks have a shape of a mushroom.
Ans. In deserts, winds usually erode the lower section of the rock more than the upper part. Such rock have narrower base and wider top and look like a mushroom.
Ii) flood plains are very fertile.
Ans. Flood plains are formed by the deposition of fine soil and other material called sediments on the river banks. As the soil and sediments are brought by flood water they are very fertile.
Iii) sea caves are turned into stacks.
Ans. Sea waves strike at the rocks. As a result cracks develop which become bigger over time and hollow like caves are formed, further erosion breaks the roof and only walls are left. These wall like features are called stacks.
Iv) building collapse due to earthquakes.
Ans. Due to heavy vibrations of earthquakes many buildings are not enough to resist it and collapse during earthquake.