1. Answer the following questions.
(i) Why do the plates move?
Answer:
The lithosphere is broken into a number of plates small and large in size known as lithosphere plates. These lithosphere plates move slowly because of the movement of molten magma inside the earth in a cyclic manner.
(ii) What are exogenic and endogenic forces?
Answer:
- The force which acts in the interior of the earth is called endogenic forces. For example, earthquake,s, and volcanos.
- The force which acts on the earth's surface such as erosion and deposition is called exogenic forces.
(iii) What is erosion?
Answer:
- Erosion is one type of exogenic force that causes the wearing away of the landscape by different agents such as water, winds, glacials, wave, etc.
(iv) How are flood plains formed?
Answer:
Flood plains are formed by the deposition of eroded material of river along with the bank. The flood plain is a fertile flat plain.
(v) What are sand dunes?
Answer:
- Sand dunes are depositional landforms made by winds in desert areas.
- When the winds let drop eroded material on the surface and formed a low hill like the structure of sand is called sand dunes.
(vi) How are beaches formed?
Answer:
- Beaches are depositional landforms formed by ocean waves. Wave deposits the eroded materials along with shore which leads to the formation of beaches.
(vii) What are oxbow lakes?
Answer:
- Oxbow lakes formed by the meandering river. Over time, the meandering loop comes closer to closer and ultimately gets cut off from the main channel. This cut off channel is oxbow lakes which is U shaped.
2. Tick the correct answer.
(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) Oxbow lakes are found in:
(a) Glaciers
(b) River valleys
(c) Deserts
Answer:
b) River valleys
3. Match the following.
(i) Glacier (a) Seashore
(ii) Meanders (b) Mushroom rock
(iii) Beach (c) River of ice
(iv) Sand dunes (d) Rivers
(v) Waterfall (e) Vibrations of earth
(vi) Earthquake (f) Sea-cliff
(g) Hard bed-rock
(h) Deserts
Answer:
(i) Glacier (c) River of ice
(ii) Meanders (d) Rivers
(iii) Beach (a) Seashore
(iv) Sand dunes (h) Deserts
(v) Waterfall (g) Hard bed-rock
(vi) Earthquake (e) Vibrations of earth
4.Give reasons.
(i) Some rocks have a shape of a mushroom.
Answer:
In desert areas, winds erode some rock faster in the lower part than the upper part; as a result, remain rock looks like a mushroom shape.
(ii) Flood plains are very fertile.
Answer:
River deposits very finer material and mineral-rich particles every year on flood plains which make flood plains fertile.
(iii) Sea caves are turned into stacks.
Answer:
Ocean wave erodes shore rock and makes shallow hollow like structure called caves. Over time, these caves become larges and only the roof of caves remains; the structure is called Sea Arch. Over time, when the roof of a sea arch falls and remains pillar-like or wall-like structure; this pillar-like structure is called stacks.
Both cave and stack are minor landforms created by the erosion process of the wave.
(iv) Buildings collapse due to earthquakes.
Answer:
Earthquakes' waves make cracks on buildings and vibration of the earth's surface leads to the collapse of buildings.
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