Class 7 Social Science - Our Environment (Geography) - Chapter Our Changing Earth NCERT Solutions | (i) Why do the plates move? (ii) What a

Observe the photographs given below. These are various features made by a river. Identify them and also tell whether they are erosional or depositional or landforms formed by both.

(i) Glacier                                      (a) Sea shore
(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

(i) Some rocks have a shape of a mushroom.
(ii) Flood plains are very fertile.
(iii) Sea caves are turned into stacks.
(iv) Buildings collapse due to earthquakes.

(i) Which is not an erosional feature of sea waves?
(a) Cliff (b) Beach (c) Sea cave

(ii) The depositional feature of a glacier is:
(a) Flood plain (b) Beach (c) Moraine

(iii) Which is caused by the sudden movements of the earth?
(a) Volcano (b) Folding (c) Flood plain

(iv) Mushroom rocks are found in:
(a) Deserts (b) River valleys (c) Glaciers

(v) Ox bow lakes are found in:
(a) Glaciers (b) River valleys (c) Deserts

(i) What is an ecosystem?

(ii) What do you mean by natural environment?

(iii) Which are the major components of the environment?

(iv) Give four examples of human made environment.

(v) What is lithosphere?

(vi) Which are the two major components of biotic environment?

(vii) What is biosphere?

(i) What are the three layers of the earth?
(ii) What is a rock?
(iii) Name three types of rocks.
(iv) How are extrusive and intrusive rocks formed?
(v) What do you mean by a rock cycle?
(vi) What are the uses of rocks?
(vii) What are metamorphic rocks?

(i) What is atmosphere?
(ii) Which two gases make the bulk of the atmosphere?
(iii) Which gas creates green house effect in the atmosphere?
(iv) What is weather?
(v) Name three types of rainfall?
(vi) What is air pressure?

(i) What is precipitation?
(ii) What is water cycle?
(iii) What are the factors affecting the height of the waves?
(iv) Which factors affect the movement of ocean water?
(v) What are tides and how are they caused?
(vi) What are ocean currents?

(i) Which are the two factors on which the growth of vegetation mostly depends?
(ii) Which are the three broad categories of natural vegetation?
(iii) Name the two hardwood trees commonly found in tropical evergreen forest.
(iv) In which part of the world are tropical deciduous forest found?
(v) In which climatic conditions are citrus fruits cultivated?
(vi) Mention the uses of coniferous forest.
(vii) In which part of the world is seasonal grassland found?

(i) What are the four means of transport?
(ii) What do you understand by the term ‘settlement’?
(iii) Which are the activities practised by the rural people?
(iv) Mention any two merits of railways.
(v) What do you understand by communication?
(vi) What is mass media?

(i) Name the continent in which the Amazon Basin is located.
(ii) What are the crops grown by the people of the Amazon Basin.
(iii) Name the birds that you are likely to find in the rainforests of the Amazon.
(iv) What are the major cities located on the River Ganga.
(v) Where is the one-horned rhinoceros found?

(a) What are the two types of deserts found in the world?
(b) In which continent is the Sahara desert located?
(c) What are the climatic conditions of the Ladakh desert?
(d) What mainly attracts tourists to Ladakh?
(e) What type of clothes the people of the Sahara desert wear?
(f) Name the trees that grow in Ladakh.

(i) Which is not a natural ecosystem?
(a) Desert (b) Aquarium (c) Forest

(ii) Which is not a component of human environment?
(a) Land (b) Religion (c) Community

(iii) Which is a human made environment?
(a) Mountain (b) Sea (c) Road

(iv) Which is a threat to environment?
(a) Growing plant(b) Growing population (c) Growing crops

(i) The rock which is made up of molten magma is
(a) Igneous (b) Sedimentary (c) Metamorphic

(ii) The innermost layer of the earth is
(a) Crust (b) Core (c) Mantle

(iii) Gold, petroleum and coal are examples of
(a) Rocks (b) Minerals (c) Fossils

(iv) Rocks which contain fossils are
(a) Sedimentary rocks
(b) Metamorphic rocks
(c) Igneous rocks

(v) The thinnest layer of the earth is
(a) Crust (b) Mantle (c) Core

(i) Caspian Sea                                         (a) Largest lake
(ii) Tide                                                      (b) Periodic rise and fall of water
(iii) Tsunami                                               (c) Strong seismic waves
(iv) Ocean currents                                   (d) Streams of water moving along definite paths

                                                                  (e) Water cycle

(i) Conduct a survey in your locality and find out how people commute to their respective workplaces using –
(a) more than two modes of transport
(b) more than three modes of transport
(c) stay within walking distance.

(ii) Mention which mode of communication you will prefer most in the following situations –
(a) Your grandfather has suddenly fallen ill. How will you inform the doctor?
(b) Your mother wants to sell the old house. How will she spread this news?
(c) You are going to attend the marriage of your cousin for which you will be absent from the school for the next two days. How will you inform the teacher?
(d) Your friend has moved out with his/her family to New York. How will you keep in touch on a daily basis?

(i) Core                                              (a) Earth’s surface
(ii) Minerals                                       (b) Used for roads and buildings
(iii) Rocks                                          (c) Made of silicon and alumina
(iv) Clay                                             (d) Has definite chemical composition
(v) Sial                                               (e) Innermost layer
                                                          (f) Changes into slate
                                                          (g) Process of transformation of the rock

(i) Man modifies his environment

(ii) Plants and animals depend on each other

(i) What is an ecosystem?

(ii) What do you mean by natural environment?

(iii) Which are the major components of the environment?

(iv) Give four examples of human made environment.

(v) What is lithosphere?

(vi) Which are the two major components of biotic environment?

(vii) What is biosphere?

(i) Walrus                                                 (a) Soft wood tree
(ii) Cedar                                                  (b) An animal of tropical deciduous forest
(iii) Olives                                                 (c) A polar animal
(iv) Elephants                                           (d) Temperate grassland in Australia
(v) Campos                                              (e) Thorny shrubs
(vi) Downs                                               (f) A citrus fruit

                                                                (g) Tropical grassland of Brazil

(i) Wet clothes take longer time to dry on a humid day?
(ii) Amount of insolation decreases from equator towards poles?

(i) Which is not a natural ecosystem?
(a) Desert (b) Aquarium (c) Forest

(ii) Which is not a component of human environment?
(a) Land (b) Religion (c) Community

(iii) Which is a human made environment?
(a) Mountain (b) Sea (c) Road

(iv) Which is a threat to environment?
(a) Growing plant(b) Growing population (c) Growing crops

(i) The name of one river is hidden in each of the sentences below. Spot it. Example:Mandira, Vijayalakshmi and Surinder are my best friends Answer: Ravi
(a) The snake charmer’s bustee, stables where horses are housed, and the piles of wood, all caught fire accidentally. (Hint: Another name for River Brahmputra)

(b) The conference manager put pad, material for reading and a pencil for each participant (Hint: A distributary on the Ganga-Brahmputra delta)

(c) Either jealousy or anger cause a person’s fall (Hint: Name of a juicy fruit!)

(d) Bhavani germinated the seeds in a pot (Hint: Look for her in West Africa)

(e) “I am a zonal champion now” declared the excited athlete. (Hint: The river that has the biggest basin in the world)

(f) The tiffin box rolled down and all the food fell in dusty potholes. (Hint: Rises in India and journeys through Pakistan)

(g) Malini leaned against the pole when she felt that she was going to faint. (Hint: Her delta in Egypt is famous)

(h) Samantha mesmerised everybody with her magic tricks. (Hint: London is situated on her estuary)

(i) “In this neighbourhood, please don’t yell! Owners of these houses like to have peace”. Warned my father when we moved into our new flat”. (Hint: colour!)

(j) ‘Write the following words, Marc!’ “On”, “go”, “in”........ said the teacher to the little boy in KG Class. (Hint: Rhymes with ‘bongo’) Now make some more on your own and ask your classmates to spot the hidden name. You can do this with any name: that of a lake, mountains, trees, fruits, school items etc.

(i) Today’s world is shrinking.