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Extra Questions for Class 7 Social Science

  

Extra Questions for Class 7 Social Science

Extra Questions for Class 7 Social Science Geography

Extra Questions for Class 7 Social Science Geography : Our Environment

Extra Questions for Class 7 Social Science History

Extra Questions for Class 7 Social Science History : Our Pasts – II

Extra Questions for Class 7 Social Science Civics

Extra Questions for Class 7 Social Science Civics : Social and Political Life – II


Environment Class 7 Extra Questions Geography Chapter 1

  

Environment Class 7 Extra Questions Social Science Geography Chapter 1

NCERT Extra Questions for Class 7 Social Science Geography Chapter 1 Environment

Prelude

Question 1.
What made Ravi sad while going to school after vacation?
Answer:
After the long vacation while going to school Ravi noticed that the only play-ground next to the school is dug up. He was told that a multi storey building would be constructed there.

This made him sad as the big playground with grass, marigolds and butterflies would be gone forever. He shared his feelings with his classmates.

Question 2.
What all are the part of our environment?
Answer:
Our Surroundings constitute environment. Buildings furniture like tables, chairs, open field, road, garbage etc. are all part of our environment. Some things like mountains, rivers, trees are created by nature. Others like chair, table, roads and clothes are made by man.

Question 3.
Why is our environment changing?
Answer:

  • It is all because of our needs.
  • They are increasing day by day.
  • We are therefore modifying and at times even destroying our natural surroundings.

Question 4.
How do human beings modify the environment?
Answer:
Environment provides the basic life support system like air, water, food and land. The man made things like car pollute the air, factories build on land, containers for food and water are the examples of modification of environment.

Question 5.
Distinguish between biotic and abiotic environments.
Answer:
Biotic Environment

  • The world of living organisms is called biotic environment.
  • Examples: Plants and animals.
    Abiotic Environment
  • The world of non-living elements is called abiotic environment.
  • Example: Land.

Question 6.
Explain with examples the different components of environment.
Answer:
Major Components of environment are – Man-made, natural and Human beings.
Major Components of the Environment:
Natural Components:

  • Land (Lithosphere).
  • Water (Hydrosphere).
  • Air (Atmosphere).
  • Living things (Organisms).

Human-made Components:

  • Buildings.
  • Parks.
  • Bridges.
  • Roads.
  • Monuments.
  • Industries.

Humans

  • Individuals
  • Family
  • Community
  • Religion
  • Education
  • Economic
  • Political situation

Examples of Human-made Environment:

  • Buildings
  • Parks
  • Bridges
  • Roads
  • Monuments
  • Industries

Environment Class 7 Extra Questions Geography Chapter 1 - 3
Question 7.
What is environment?
Answer:
The surrounding in which we live forms environment. It is the basic life support system having natural and man-made components.

  • The people, the place, the things, the nature and the living organisms that surround us are called environment.
  • It is a combination of natural and human made phenomena.
  • The natural environment refers to both biotic and abiotic conditions existing on the earth.
  • Human environment reveals the activities, creations and interactions among human beings.

Natural Environment

Question 1.
What comprises natural environment?
Answer:
Land, air, water, plants and animals are all the part of natural environment.

Question 2.
Describe lithosphere and hydrosphere.
Answer:
Lithosphere

  • It is the solid crust or the hard top layer of the earth.
  • It is made up of rocks and minerals.
  • It is covered by a thin layer of soil.
  • It is an irregular surface with various landforms like mountains, plateaus, plains, valleys etc.
  • Landforms spread over the continents and also on the ocean floors.

Lithosphere provides us the following:

  • Forests.
  • Grasslands for grazing.

Environment Class 7 Extra Questions Geography Chapter 1-2

  • Land for agriculture and
  • Human settlements.
  • It is also a source of mineral wealth.

Hydrosphere is the domain of water.

  • It comprises various sources of water.
  • The different types of water bodies like rivers, lakes, seas, oceans, etc. are its major components.
    • It is essential for all living organisms.

Question 3.
Give an account of the atmosphere.
Answer:

  • The atmosphere is the thin layer of air that surrounds the earth.
  • The gravitational force of the earth holds the atmosphere around it.
  • It protects us from the harmful rays and scorching heat of the sun.
  • It consists of numerous gases, dust and water vapour.
  • The changes in the atmosphere produce changes in the weather and climate.

Question 4.
Define the term ‘Biosphere’.
Answer:
Biosphere: Plants and animals found in the narrow strip at the junction of lithosphere, atmosphere and hydrosphere together make biosphere.

What is Ecosystem?

Question 1.
What do you understand by the term “Ecosystem”?
Answer:
Ecosystem: An ecosystem is formed by the interaction of all living organisms with one another and with the physical and chemical factors of the environment in which they live. All are linked by transfer of energy and material. They are interdependent.

Question 2.
Compare and contrast the climatic conditions of Kerala and Rajasthan.
Answer:
Kerala, a southern state of India gets ample rainfall. It has lush green vegetation and coconut plantations.
Rajasthan, on the other hand, gets very less rainfall. It has thorny bushes, kikar and babul as vegetation.

Question 3.
Name some animals found in deserts.
Answer:
Camels, snakes, lizards, insects are found in deserts.

Question 4.
Why do the animals and vegetation vary from place to place?
Answer:
Animals and vegetation vary from place to place because

  • They are dependent on their immediate surroundings.
  • They depend on the environmental conditions like climate, soil, water etc.
  • All of them sire interdependent on each other.

Question 5.
What forms the ecosystem? Give some examples of ecosystems.
Answer:
The relationship between the living organisms and their surroundings form the ecosystem. Rain forest, grassland, deserts, mountains, lake, river, ocean and pond are some of the examples of ecosystems.

Question 6.
Do you think the park in which Ravi and his friends played formed an ecosystem?
Answer:
Yes.

Human Environment

Question 1.
Define barter system.
Answer:
Barter system is the exchange of goods without the use of money.

Question 2.
What has brought a change in interaction between humans and their surroundings?
Answer:
Human being modifies nature according to their need. Early humans adapted themselves to their natural surroundings. They led a simple life fulfilling their needs from nature.

With changes in needs new methods and technologies were invented. Settled life brought agriculture domestication of animals. Invention of wheel, surplus food led to development of trade and commerce. Barter system emerged.

Industrial revolution, changes in transportation increased production. Growth in communication system made life easier and speedy. Humans learned new ways to use and change the surroundings.

Question 3.
What is important for a harmonious life?
Answer:
Certain things are used in a certain way like watermelon in summer or roasted peanuts in winter. We need a balance between natural and human environment. Human beings must use their natural environment in a sustainable way to maintain the balance.

Question 4.
Why did Nurie invited Ravi to her place?
Answer:
Ravi was upset at losing his playground to building construction .Nurie invited him to her home in Mizoram in the lush green surroundings.

Objective Type Questions

Question 1.
Fill in the blanks with appropriate words:
1. Hydrosphere is a part of …………………………
2. Two main constituents of environment are ………………………… and ………………
3. ………………………… is the hard top layer of the earth.
4. ………………………… modify the natural environment.
Answer:
1. biosphere
2. natural, man-made
3. Lithosphere
4. Human beings

Question 2.
Write whether the given statements are true or false:
1. Landforms are found only over continents.
2. Trade in which goods are exchanged without the use of money is called barter system.
3. Gravitational force of the earth holds the atmosphere around it.
4. No life can exist in biosphere.
5. Abiotic environment consists of living organism.
Answer:
1. False
2. True
3. True
4. False
5. False

Question 3.
Match the contents of Column A with that of Column B.
Environment Class 7 Extra Questions Geography Chapter 1 - 2Answer:
1. (c)
2. (d)
3. (a)
4. (b)

Multiple Choice Questions

Prelude

Question 1.
Which one of the following is a basic life support system?
(a) Music system
(b) Environment
(c) Transportation
(d) None of these
Answer:
(b) Environment

Question 2.
Which one of the following is created by nature?
(a) Cars, scooters and buses
(b) Mountains, rivers and trees
(c) Roads, books, pen and copies
(d) All of these
Answer:
(b) Mountains, rivers and trees

Natural Environment

Question 1.
The domain of water is referred to
(a) hydrosphere
(b) lithosphere
(c) atmosphere
(d) biosphere
Answer:
(a) hydrosphere

Question 2.
What do plant and animal kingdom make together?
(a) Biosphere
(b) Hydrosphere
(c) Atmosphere
(d) All of these
Answer:
(a) Biosphere

What is Ecosystem?

Question 1.
Which one of the fallowing animals is called the ship of the desert?
(a) Camel
(b) Goat
(c) Cow
(d) Dogs
Answer:
(a) Camel

Question 2.
When is the World Environment Day celebrated every year?
(a) 25th December
(b) 23rd June
(c) 26th January
(d) 5th June
Answer:
(d) 5th June

Human Environment

Question 1.
Who interacts with the environment and modify it according to their needs?
(a) Human beings
(b) Animals
(c) Rivers
(d) Mountains
Answer:
Human beings

Question 2.
Which one of the following is not a threat to environment?
(a) Growing population
(b) Growing plants
(c) Growing industries
(d) All of these
Answer:
Growing plants

Inside Our Earth Class 7 Extra Questions Geography Chapter 2

  

Inside Our Earth Class 7 Extra Questions Social Science Geography Chapter 2

NCERT Extra Questions for Class 7 Social Science Geography Chapter 2 Inside Our Earth

Prelude

Question 1.
How is the earth a dynamic planet?
Answer:

  • The earth is our homeland.
  •  It is a dynamic planet.
  • It is constantly undergoing changes inside and outside.

Interior of the Earth

Question 1.
Have you ever wondered what lies in the interior of the earth? What is the earth made up of?
Ans.

  •  Yes.
  • The interior has three major layers of rocks of different densities.
  • The earth is made up of rocks.

Question 2.
Describe the interior of the earth.
Answer:
Interior of the Earth:
The earth is made up of several concentric layers with one inside another, just like an onion.
Crust:

  • The uppermost layer on the earth’s surface is called the crust.
  •  It is the thinnest of all the layers.
  • It is about 35 km, thick on the continental masses and only 5 km thick on the ocean floors.
  • Main minerals constituent of the continental mass are silica and alumina.
  • It is thus called sial (si – silica and al – alumina).

Inside Our Earth Class 7 Extra Questions Geography Chapter 2 - 2

  • The oceanic crust mainly consists of silica and magnesium.
  • It is therefore called sima (si – silica and ma – magnesium).

Inside Our Earth Class 7 Extra Questions Geography Chapter 2 - 3

Mantle

  • Just beneath the crust is the mantle.
  • It extends up to a depth of 2900 km below the crust.

Core

  • The innermost layer is the core with a radius of about 3500 km.
  • It is mainly made up of nickel and iron.
  • Hence it is called nife (ni—nickel and fe—ferrous i.e., iron).
  • The central core has very high temperature and pressure.

Rocks and Minerals

Question 1.
What is earth’s crust made up of?
Answer:
Earth’s crust is made up of different type of rocks. Rock is a natural mass of mineral matter. It is of different sizes, colours and texture and shapes. Earth is made up of sedimentary, igneous or metamorphic rocks.

Question 2.
Describe igneous rocks.
Ans.
Igneous Rocks

  • The molten rock material is called magma.
  • When it cools, it becomes solid.
  • Rocks formed in this way are called igneous rocks.
  • They are also called primary rocks because other rocks are formed out of these rocks.

There are two types of igneous rocks.

  • Intrusive Rocks and
  • Extrusive Rocks

Formation of Extrusive and Intrusive Rocks:

  • Due to extreme heat in the interior of the earth, rocks are found in the form of molten material called magma.
  • When magma comes out on the surface of the earth, it cools down and turns into solid rocks. Such rocks are termed as extrusive rocks.

Examples:

  • Basalt.
  • Deccan Trap is built of basalt.

When the molten magma cools down within the interior of the earth, it becomes solid to form intrusive rocks.
Examples:

  • Granite
  • Garbo

Question 3.
What is lava?
Answer:
Lava is the hot red magma coming out from the interior of the earth to the surface. It cools down and become solid.

Question 4.
What are two types of Igneous rocks?
Answer:
Igneous rocks are formed by cooling of the lava. When the lava cools down on the crust it forms extrusive igneous rock for example basalt. They have grained structure.
Sometimes when it cools down deep inside the crust it forms intrusive igneous rocks. They have large grains for example Granite. Grinding stones are made of granite.

Question 5.
Define the term sediment.
Answer:
Rocks due to cracks and hitting, breakdown into smaller fragments called sediments.

Question 6.
Give an account of sedimentary rocks.
Answer:
Sedimentary Rocks
The small particles are called sediments.

  • These sediments are transported and deposited by wind, water etc. in low areas.
  • These loose sediments are compressed and hardened to form layers of rocks.
  • These layered rocks are called sedimentary rocks.

Examples:

  • Sandstone.
  • These rocks also contain fossils of plants, animals and other micro-organisms that once lived on them.

Inside Our Earth Class 7 Extra Questions Geography Chapter 2 - 4

Question 7.
What are Fossils?
Answer:
Fossils:
The remains of dead plants and animals trapped in the layers of rocks are known as fossils.

Question 8.
How are metamorphic rocks formed?
Answer:
Igneous and Sedimentary rocks changes into metamorphic rocks under heat and pressure.

Metamorphic Rocks:
When under heat and pressure igneous rocks and sedimentary rocks change their form and more precious rocks are formed to be known as metamorphic rocks.
Examples:

  • Granite into granite gneiss.
  • Coal into slate.
  • Slate into schist.
  • Limestone into marble.

Limestone is changed into marble due to the following reasons:

  • The overlying layers of rocks put pressure on the underlying rocks.
  • From surface to interior of the earth, temperature and heat go on increasing.
  • Due to pressure and heat, the original limestone changes into marble.g

Question 9.
What are the uses of rocks?
Answer:
Uses of Rocks:

  • Hard rocks are used in making buildings and barrages.
  • Houses and buildings are built of rocks (stones, slates, granite, marble).
  • Stones are used in numerous games:
  • Seven stones (phitthoo).
  • Hop scotch (stapu, kit kit).
  • Five stones (gitti).
  • Rocks (stones and slates) are used in building bridges, embankments.

Question 10.
Briefly describe the ‘rock cycle’.
Answer:
One rock changes into another under certain conditions in a cyclic manner.
Molten magma cools down and solidify to form igneous rocks. These rocks are broken down due to pressure and climatic conditions into sediments.
These are transported and deposited to form sedimentary rocks. The igneous and sedimentary rocks under heat and pressure change into metamorphic rocks.
These metamorphic rocks under great heat and pressure melt down to form molten magma. This again cools down to form igneous rocks. This process of transformation of rocks is called ‘rock cycle’.

Question 11.
What are minerals? How are minerals important to us?
Answer:
Minerals:

  • Rocks are made up of different minerals.
  • Minerals are naturally occurring substances which have certain physical properties and definite chemical composition.
  • Minerals are very important to us.
  • Some are used as fuels.

Examples:

  • Coal.
  • Natural gas.
  • Petroleum.

They are also used in industries as energy and raw material.
Examples:

  • Iron.
  • Aluminium.
  • Gold.
  • Uranium.

They are used in medicine, in fertilisers etc.

Objective Type Questions

Question 1.
Fill in the blanks with appropriate words:
1. Lava is the molten magma from ……………………… of the earth’s surface.
2. Like a ………………………, the earth is made up of ……………………… layers.
3. Crust is about ……………………… km on the continental mass and ……………………… km on the
ocean floor.
4. Mantle forms about ……………………… of the earth’s volume.
5. Core has a radius of about ……………………… km and has very high temperature and ………………………
6. Limestone under excessive heat and pressure changes into ………………………
Answer:
1. interior
2. onion, concentric
3. 35 and 5
4. 16%
5. 3500, pressure
6. marble

Question 2.
State whether the given statements are true or false:
1. Crust is the thickest of all the layers.
2. Core is the innermost layer of the earth.
3. Mantle extends up to the depth of 2900 km.
4. The loose sediments are hardened to form metamorphic rocks.
5. Deccan plateau is made up of basalt.
6. Fossils are remains of dead plants and animals.
Answer:
1. False
2. True
3. True
4. False
5. True
6. True

Question 3.
Match the contents of Column A with that of Column B.
Inside Our Earth Class 7 Extra Questions Geography Chapter 2 - 1
Answer:
1. (d)
2. (e)
3. (f)
4. (d)
5. (b)
6. (c).

Multiple Choice Questions

Prelude

Question 1.
Where is the deepest mine in the world located?
(a) South America
(b) South Africa
(c) South India
(d) South Australia
Answer:
(b) South Africa

Question 2.
The depth of the deepest mine in South Africa is
(a) one km
(b) two km
(c) three km
(d) four km
Answer:
four km

Interior of the Earth

Question 1.
The upper most layer of the earth’s surface is called
(a) the crust
(b) the brust
(c) the roads
(d) the forest
Answer:
(c) the roads

Question 2.
What is the radius of the earth?
(a) 3671 km
(b) 7163 km
(c) 6371 km
(d) 1736 km
Answer:
(c) 6371 km

Rocks and Minerals

Question 1.
Any natural mass of mineral matter that makes up the earth’s crust is called a
(a) rock
(b) road
(c) sediment
(d) none of these
Answer:
(a) rock

Question 2.
The sediments are transported and deposited by
(a) wind
(b) water
(c) wind and water
(d) none of these
Answer:
(c) wind and water

Question 3.
The process of transformation of the rock from one form to another is known as
(a) road cycle
(b) food cycle
(c) rock cycle
(d) all of these
Answer:
rock cycle

Question 4.
Which rock is the molten magma made up of?
(a) Igneous
(b) Metamorphic
(c) Sedimentary
(d) None of these
Answer:
Igneous

Question 5.
What is the latin term of Igneous?
(a) Ignis
(b) Sedimentum
(c) Metamorphose
(d) None of these
Answer:
Ignis

Question 6.
Rocks which contain fossils are called
(a) metamorphic rocks
(b) igneous rocks
(c) core
(d) sedimentary rocks
Answer:
sedimentary rocks

Our Changing Earth Class 7 Extra Questions Geography Chapter 3

  

Our Changing Earth Class 7 Extra Questions Social Science Geography Chapter 3

NCERT Extra Questions for Class 7 Social Science Geography Chapter 3 Our Changing Earth

Prelude

Question 1.
What are lithospheric plates?
Answer:

  • The lithosphere is broken into numerous pieces.
  • These big pieces are called lithospheric plates.
  • The earth’s crust consists of several large and small, rigid, irregularly shaped plates/pieces.
  • The movement of these plates causes changes on the surface of the earth.

Question 2.
Why do the lithospheric plates move slowly?
Answer:
The lithospheric plates move slowly because of the slow movement of molten magma inside the earth in a circular manner.

Question 3.
What are the two types of the earth’s forces?
Answer:

  • The earth’s movements are divided on the basis of the forces which cause them.
  • The forces which act in the interior of the earth are called endogenic forces.
  • The forces that work on the surface of the earth are called exogenic forces.
  • Endogenic forces sometimes produce sudden movements.
  • At other times they produce slow movements.
  • Sudden movements are earthquakes and volcanoes.
  • They cause mass destruction over the surface of the earth.

Our Changing Earth Class 7 Extra Questions Geography Chapter 3 - 1
Question 4.
Define a volcano.
Answer:
A volcano is a vent or a hole in the earth’s crust through which molten material erupts suddenly.
Our Changing Earth Class 7 Extra Questions Geography Chapter 3 - 2

Question 5.
What are earthquakes? Define focus and epicentre.
Answer:
Earthquake

  • When the lithosphere plates move, the surface of the earth vibrates.
  • The vibrations travel all around the earth.
  • These vibrations are called earthquake.

Focus:
The place or point in the crust where the movement starts is called Focus.

Epicentre:
The place or the surface above the focus is called Epicentre.

  • Vibrations travel outwards from the epicentre as waves.
  • Greatest damage occurs closest to the epicentre.
  • The strength of the earthquake decreases, going away from the centre.

Our Changing Earth Class 7 Extra Questions Geography Chapter 3 - 3

Question 6.
What are three types of earthquake waves?
Answer:
There are three types of earthquake waves:

  • P waves or longitudinal.
  • S waves or transverse waves.
  • L waves or surface waves.

Question 7.
How can we minimise the impact of an earthquake?
Answer:

  • Earthquakes cannot be predicted.
  • Their impact can certainly be minimised if we are prepared before hand.

Question 8.
Give an account of some common earthquake prediction methods adopted locally by people.
Answer:
Some of the common earthquake prediction methods adopted locally by people are:

  • Wild animal behaviour.
  • Agitated fish in the ponds.
  • Snakes coming out to the surface from their holes.
  • Animals trying to untie themselves and run away.
  • Birds leaving their nests and beginning to chatter loudly.
  • Aborigines beginning to run to higher grounds.

Question 9.
What is seismograph? How is the magnitude of earthquake measured?
Answer:

  • An earthquake is measured with a machine.
  • It is called a seismograph.

The magnitude of the earthquake is measured on Richter scale.

  • An earthquake of 2.0 or less is felt only a little.
  • An earthquake over 5.0 causes damage from things falling.
  • A 6.0 or higher magnitude is considered very strong and 7.0 is classified as a major earthquake.

Question 10.
Explain Earthquake preparedness.
Answer:
Earthquake Preparedness:
When an earthquake strikes we should do the following:

  • We should be in a safe spot like: under a kitchen counter, table or desk.
  • We should stand against an inside comer or wall.
  • We should stay away from fire places, areas around chimneys, windows that shatter including mirrors and picture frames.
  • We should be prepared by arousing awareness amongst our friends and family members.
  • We should face any disaster confidently.

NOTES: Case Study Bhuj Earthquake:

  • An earthquake measuring 6.9 on richter scale hits Bhuj in Gujarat.
  • Schools worst affected.
  • Communication water power supply affected
  • Hundreds of fire started
  • Emergency declared and CM appeals for help.

Major Land Forms

Question 1.
What are the two processes which continuously wear away the landscape? Explain them.
Answer:
The Processes:
The landscape is continuously worn away by two processes.
They are:

  • Weathering and erosion.
  • Weathering is the breaking up of rocks on the earth’s surface.
  • Erosion is the wearing away of the landscape by different agents like water, wind and ice.
  • The eroded material is carried away or transported by water, wind etc.
  • They deposit material eventually.
  • This process of erosion and deposition creates different landforms on the surface of the earth.

Work of a River

Question 1.
What is a waterfall? Explain with example.
Answer:
When the rivers tumble at steep angle over the hard rocks of a deep steep valley it forms a waterfall.
For example: Victoria waterfalls or Niagara waterfall.

Question 2.
Describe the work of a river.
Answer:
Work of a River:

  • Running water in the river erodes the landscape.
  • When the river tumbles at steep angle over very hard rocks or down a steep valley side, it forms a waterfall.
  • When the river enters the plain it twists, turns and forms large bends. These bends are known as meanders.

Due to continuous erosion and deposition along the sides of the meander, the ends of the meander loop come closer and closer.

  • In due course of time the meander loop cuts-off from the river and forms a cut-off lake.
  • It is called an ox-bow lake.
  • At times the river overflows its banks.
  • This leads to the flooding of the neighbouring areas.
  • The flood water deposits layers of fine soil and other material.
  • They’are called sediments, along its banks.
  • This leads to the formation of a flat fertile land called a flood plain.
  • The raised banks are called levees.

As the river approaches the sea, the speed of the running water decreases.

  • The river begins to break up into a number of streams. They are called distributaries.
  • Now the river becomes so slow that it begins to deposit its load.
  • Each distributary forms its own mouth.
  • The collection of sediments from all the mouths forms a delta, the triangular shaped land mass.

Work of Sea Waves

Question 1.
Write a note on the work of sea-waves.
Answer:
Work of Sea Waves

  • Erosion and deposition of the sea waves form coastal land forms.
  • Sea waves continuously strike at the rocks.
  • Cracks develop.
  • In course of time they become larger and wider.
  • Hollow like caves are formed on the rocks.
  • They are called sea caves.
  • As caves become bigger and bigger only the roofs of the caves remain. This leads to formation of Sea arches.
  • Continuous erosion breaks the roofs and only walls are left.
  • These wall-like features are called stacks.
  • The steep rocky coast rising almost vertically above sea water is called sea cliff.
  • The sea waves deposit sediments along the shores.
  • This leads to formation of sea beaches.

Work of Ice

Question 1.
Describe the work of ice.
Answer:
Work of Ice:

  • Glaciers are “rivers” of ice.
  • They too erode the landscape by bulldozing soil and stones to expose the solid rock below.
  • Glaciers carve out deep hollows.
  • As the ice melts they get filled up with water and become beautiful lakes in the mountains.
  • The material carried by the glacier like big and small rocks, sand, silt gets deposited.
  • These deport from glacial moraines.

Work of Wind

Question 1.
Give an account of the work of wind.
Answer:
Work pi Wind:
An active agent of erosion and deposition in the deserts is wind.
In deserts there are numerous rocks with a shape of a mushroom.

  • They are commonly called mushroom rocks.
  • Winds erode the lower section of the rock more than the upper part.
  • Such rocks have narrower base and wider top.

When the wind blows, it lifts and transports sand from one place to another.

  • When it stops blowing, the sand falls and gets deposited in low hill like structures.
  • These are called sand dunes.

When the grains of sand are very fine and light, the wind carries it over very long distances.

  • When such a sand is deposited in large areas, they are called loess. Large deposits of loess are found in China.

Objective Type Questions

Question 1.
Fill in the blanks with appropriate words:
1. Magma inside the earth moves in a ………………………. motion.
2. A ………………………… is a vent in the earth’s crust through which molten material comes
out.
3. The place in the crust where the earthquake starts is called ……………………..
4. The processes of …………………………….. and ………………………. create different landform on the surface of earth.
5. Deposition of layers of fine soil along the bank of rivers forms …………………………….
6. Sand deposits over larger areas are called………………………….
Answer:
1. circular
2. volcano
3. epicentre
4. erosion, deposition
5. flood plains
6. loess,

Question 2.
Write whether the given statements are true or false:
1. Sudden movements like earthquake do not cause mass destruction.
2. Deposition is breaking up of rocks on the earth’s surface.
3. Wearing away of the land by different agents like water, wind and ice is called erosion.
4. Sea caves become bigger and only the roof remains forming the sea arches.
5. Moraine is a depositional feature of glaciers,
6. River is an agent of erosion and deposition in the desert.
Answer:
1. False
2. False
3. True
4. True
5. True
6. False.

Question 3.
Match the contents of Column A with that of Column B
Our Changing Earth Class 7 Extra Questions Geography Chapter 3 - 4
Answer:
1. (b)
2. (d)
3. (f)
4. (g)
5. (a)
6. (c).

Multiple Choice Questions

Prelude

Question 1.
The earth’s crust is broken into a number of huge parts. They are called
(a) lithospheric plates
(b) metamorphic plates
(c) sedimentary plates
(d) none of these
Answer:
lithospheric plates

Question 2.
Which one of the following forces originates in the interior of the earth?
(a) Exogenic forces
(b) Endogenic forces
(c) Both (a) and (b)
(d) None of these
Answer:
Endogenic forces

Question 3.
Sudden movements in the earth are called
(a) earthquakes
(b) building mountains
(c) focus
(d) none of these
Answer:
earthquakes

Question 4.
The place on the surface above the focus is known as
(a) epicentre
(b) focus
(c) forces
(d) lithosphere
Answer:
epicentre

Question 5.
What is the name of the instrument used for measuring earthquake?
(a) Thermometer
(b) Seismograph
(c) Weighing machine
(d) All of these
Answer:
(b) Seismograph

Question 6.
On which scale is the earthquake measured?
(a) Plane scale
(b) Richter scale
(c) Compass
(f) Divider
Answer:
Richter scale

Major Land Forms

Work of a River:

Question 1.
In which continent is the highest waterfall ‘Angel Falls of Venezuela’ located?
(a) South America
(b) South Africa
(c) South India
(d) North India
Answer:
South America

Question 2.
Where is ‘Niagara falls’ located?
(а) On the border between Canada and USA
(b) On the border between India and China
(c) On the border between India and Pakistan
(d) On the border between India and Nepal
Answer:
On the border between Canada and USA

Question 3.
The triangular collection of sediments at the mouth of a river forms
(a) beach
(b) delta
(c) arches
(d) glaciers
Answer:
delta

Work of Sea Waves

Question 1.
The steep rocky coast rising almost vertically above the sea water is called
(a) sea cliff
(b) beach
(c) sea cave
(d) erosion
Answer:
sea cliff

Work of Ice

Question 1.
Which of the following is an example of a glacier
(a) Gangotri
(b) Aravali
(c) both of these
(d) none of these
Answer:
Gangotri

Work of Wind

Question 1.
Deposition of sand in a low hill like structure is known as a: ‘
(a) Glacier
(b) Sand dimes
(c) Hill
(d) Desert
Answer:
Sand dimes

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