CHAPTER -- OUR CHANGING EARTH , BACK EXERCISE , CLASS 7th ,( GEO)
CHAPTER -- OUR CHANGING EARTH
CLASS 7th ,( GEO)
Q1. Why do the plates move?
Ans; The tectonic plates move because of the movement of molten magma inside the earth.
Q2. What are Exogenic and Endogenic forces?
Ans; The forces which act in the interior of the earth are called as Endogenic forces. Examples are earthquakes and volcanoes.
The forces that work on the surface of the earth are called as Exogenic forces. Examples are Erosional and Depositional.
Q3. What is erosion?
Ans; the wearing away of landscape by different agents like wind, water and ice.
Q4. How are flood plains formed?
Ans; when the rivers get flooded, it deposits layers of fine soil and other material called sediments along its banks. This leads to the formation of a flat fertile floodplain.
Q5. What are sand dunes?
Ans; When the wind blows, it lifts and transports sand from one place to another, and gets deposited in low hill – like structures. These are called sand dunes
Q6. How are beaches formed?
Ans; The sea waves deposit sediments along the shores forming beaches.
Q7. What are ox bow lakes?
Ans; Due to continuous erosion and deposition along the sides of the meander, the ends of the meander loop come closer and closer and the river forms a cut-off lake, also called an ox-bow lake.
Ans; The tectonic plates move because of the movement of molten magma inside the earth.
Q2. What are Exogenic and Endogenic forces?
Ans; The forces which act in the interior of the earth are called as Endogenic forces. Examples are earthquakes and volcanoes.
The forces that work on the surface of the earth are called as Exogenic forces. Examples are Erosional and Depositional.
Q3. What is erosion?
Ans; the wearing away of landscape by different agents like wind, water and ice.
Q4. How are flood plains formed?
Ans; when the rivers get flooded, it deposits layers of fine soil and other material called sediments along its banks. This leads to the formation of a flat fertile floodplain.
Q5. What are sand dunes?
Ans; When the wind blows, it lifts and transports sand from one place to another, and gets deposited in low hill – like structures. These are called sand dunes
Q6. How are beaches formed?
Ans; The sea waves deposit sediments along the shores forming beaches.
Q7. What are ox bow lakes?
Ans; Due to continuous erosion and deposition along the sides of the meander, the ends of the meander loop come closer and closer and the river forms a cut-off lake, also called an ox-bow lake.
2. Tick the correct Answers :
(i) Which is not an erosional feature of sea waves?
(a) Cliff (b) Beach (c) Sea cave
Answer :
b) Beach.
(ii) The depositional feature of a glacier is:
(a) Flood plain (b) Beach (c) Moraine
Answer (c)Moraine
(iii) Which is caused by the sudden movements of the earth?
(a) Volcano (b) Folding (c) Flood plain
Answer : (a)Volcano
(iv) Mushroom rocks are found in:
(a)Deserts (b) River valleys (c) Glaciers
Answer : (a)Deserts
(v) Ox bow lakes are found in:
(a) Glaciers (b) River valleys (c) Deserts
Answer : b)Rivervalleys3. Match the following.
Answer :
| 1.Glacier | (c) River of ice |
| 2.Meanders | (d) Rivers |
| 3.Beach | (a) Sea shore |
| 4.Sand dunes | (h) Deserts |
| 5.Waterfall | (g) Hard bed rock |
| 6.Earthquake | (e) Vibrations of earth |
4.Give reasons.
(i) Some rocks have a shape of a mushroom.
(i) Some rocks have a shape of a mushroom.
(i) In deserts, one can see rocks in the shape of a mushroom—with a narrower base and a wider top. These are known as mushroom rocks. Such rocks are formed when the winds erode the lower section of a rock more than the upper part.
(ii) Flood plains are very fertile.
(ii) Flood plains are formed as a result of the depositional activity of rivers. Rivers carry along with them eroded material like fine soil and sediments. When it overflows its banks, it deposits the eroded material and causes flood plains to be formed. The deposited material makes the land fertile.
(iii) Sea caves are turned into stakes.
Ans; Due to the erosion the roof of the sea arches are break down and only walls are left. These wall like features are called stacks.
(iv) Building collaspes due to an earth quake.
Ans; Due to the high vibrations of the earth quake buildings are not withstanding thus it fell down.
(ii) Flood plains are very fertile.
(ii) Flood plains are formed as a result of the depositional activity of rivers. Rivers carry along with them eroded material like fine soil and sediments. When it overflows its banks, it deposits the eroded material and causes flood plains to be formed. The deposited material makes the land fertile.
(iii) Sea caves are turned into stakes.
Ans; Due to the erosion the roof of the sea arches are break down and only walls are left. These wall like features are called stacks.
(iv) Building collaspes due to an earth quake.
Ans; Due to the high vibrations of the earth quake buildings are not withstanding thus it fell down.
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