Class 7 Social Science - Our Environment (Geography) - Chapter Our Changing Earth NCERT Solutions | (i) Glacier        &

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) Why do the plates move?
(ii) What are exogenic and endogenic forces?
(iii) What is erosion?
(iv) How are flood plains formed?
(v) What are sand dunes?
(vi) How are beaches formed?
(vii) What are ox bow lakes?

(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

FOR FUN

                                                     Desert Game

This is a class room activity involving all the students. The teacher will create a list of desert creatures. The number of the creatures should be same as the number of students in the class. The creatures can be picked up from the categories of mammals, birds and reptiles. Mammals can include – camel, yak, fox, sheep, goat, antelope... Birds – raven, eagle, vulture, turkey... Reptiles – snakes ... Assign one desert creature to each student. Ask the student to write three characteristics of the creature on plain sheet of paper. (students can use index cards of size 10 cm × 15 cm). Questions such as - in what type of deserts it is
found? Major adaptation? Use to man? These characteristics will be used as clues in the guessing game. On the board make three columns – mammals, birs and reptiles. Paste a sheet of paper in the column under the particular category. The class can be divided in three to four groups. They will compete against each other in the ‘desert game’. Each group now
takes turn in guessing the correct answer. Explain to the class that they have to guess what animal matches the characteristics listed on the paper. For example:
• Animal of hot desert
• Has double set of eyelashes to keep away the sand
• The hide is used for making water bottles
The correct answer is ‘camel’. Within the group there will be a student who has prepared the card. That student should not answer. Ten points are awarded for the correct answer. This game will enable students to understand the desert. You can play the same game by taking different types of fruits, flora and the clothes the people wear.

(i) On an outline map of the Indian Sub-continent, draw the rivers Ganga and Brahmaputra from the source to the mouth. Also show the important tributaries of both the rivers.
(ii) On the political map of South America, draw the equator. Mark the countries through which the equator passes.

(i) Which is NOT a means of communication?
(a) telephone (b) books (c) table

(ii) Which type of road is constructed under the ground?
(a) fly over (b) expressways (c) subways

(iii) Which mode of transport is most suitable to reach an island?
(a) ship (b) train (c) car

(iv) Which vehicle does not pollute the environment
(a) cycle (b) bus (c) aeroplane

(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?