9th Std Social Science Term 3 Solution | Lesson.4 Man And Environment

Lesson.4 Man And Environment

9th Standard Social Science Book Term 3 - Man And Environment

Lesson.4 Man And Environment

I. Choose the correct answer

1. All external influences and factors that affect the growth and development of living organisms is ……………

  1. Environment
  2. Ecosystem
  3. Biotic factors
  4. Abiotic factors

Ans : a) Environment

2. The ‘World Population Day’ is observed on …………… every year.

  1. August 11th
  2. September 11th
  3. July 11th
  4. January 11th

Ans : c) July 11th

3. The statistical study of human population is ……………

  1. Demography
  2. Morphology
  3. Etymology
  4. Seismography

Ans : a) Demography

4. The extraction of valuable minerals and other geological minerals from the mines, is ……………

  1. Fishing
  2. Lumbering
  3. Mining
  4. Agriculture

Ans : c) Mining

5. The Secondary sector of the economy produces …………… from raw materials.

  1. Semi finished goods
  2. Finished goods
  3. Economic goods
  4. raw materials

Ans : b) Finished goods

6. Gradual increase of the earth’s temperature by the Green house gases in the atmosphere is called …………….

  1. Acid rain
  2. thermal pollution
  3. Global warming
  4. Deforestation

Ans : c) Global warming

Consider the given statements and choose the right option given below

8. Assertion(A): Ozone layer in the stratosphere is considered as a protective shield.

Reason(R): It prevents the UV radiation from reaching the earth’s surface.

  1. A and R are correct and A explains R
  2. A and R are correct, but A does not explain R
  3. A is incorrect but R is correct
  4. Both A and R are incorrect

Ans : a) A and R are correct and A explains R

9. Assertion(A): In tertiary activities, instead of producing goods by themselves, they are in the process of production.

Reason(R): People in Tertiary activities are purely eco friendly.

  1. Both A and R are incorrect
  2. A and R are correct but A does not explain R
  3. A is correct and R is incorrect
  4. A and R are correct and A explains R

Ans : c) A is correct and R is incorrect

II Match the following

1. Loudspeaker Push factor
2. Rio de Janeiro, Brazil Pull factor
3. Cruciform settlement noice pollution
4. Natural disaster T- shaped settlement
5. Better living conditions Earth Summit, 1992
Ans : 1 – C, 2 – E, 3 – D, 4 – A, 5 – B

III. Answer the following in brief: 

1. What do you mean by the term ‘density of population’?

  • Density of population refers to the number of people living per square kilometre.
  • Large area with less number of people is known as sparsely populated area.
  • Similarly, smaller the area with a large number of people, it is said to be densely populated.

Population Density = Total population / Total land area

2. What is ‘black death’?

  • The Black Death is estimated to have killed 30 – 60 percent of Europe’s total population during the 14th century.
  • The dominant explanation for black death is attributed to the outbreak of plague.

3. Where do we have high and low densities of population?

  • We have high density (above 50 people per sq.km) in East Asia, South Asia, North West Europe & Eastern North America.
  • Areas of low density (less than 10 people per sq.km) are Central Africa, Western Australia, Northern Russia and Canada.

4. Write any two ways of how the locals and the government restored Palk Bay.

  • Mangrove trees offer coastal protection by checking erosion.
  • Saplings of native species of plants and trees are planted and taken care by the government.
  • The local communities are actively involved in the conservation and restoration of the mangroves.
  • Education and awareness programmes about mangrove ecosystem are being undertaken

5. Define.

i) Population growth ii) Infant Mortality Rate iii) Census iv) Sustainable Development

i) Population growth:

  • Population is a dynamic phenomenon where the number, distribution and composition are constantly changing.
  • Population growth refers to an increase in the number of people who reside in a particular area during a particular period.

ii) Infant Mortality Rate:

  • The number of deaths under one year of age for every 1000 live births in a year is known as Infant mortality rate.
  • Example – In 2016, the infant mortality rate was 17 per 1000 live births.

iii) Census:

  • Census is an official enumeration of population carried out periodically.
  • It records information about the characteristics of population such as age, sex, literacy and occupation.
  • Denmark was the first country in modern world to conduct a census.
  • In India, the first census was carried out in the year 1872.

iv) Sustainable Development:

Sustainable development is development that meets the needs of the present without compromising the ability of future generation to meet their own needs

IV. Distinguish between

1. Birth rate and Death Rate

Birth rate Death Rate
1. It indicates the number of live births per 1000 people in a year. 1000 people in a year. It indicates the number of deaths under one year of age for every 1000 live births in a year
2. It is one of the reasons for the population growth. It is one of the reason for the decrease of the population

2. Emigration and Immigration

Emigration Immigration
1. 1. It means moving out or to leave a place. It means to enter or come into a new country for the purpose of settling there.
2. Events like civil war, internal disturbances make the people to another place or area. Higher education and job opportunity attracts the people to that area or country.

3. Rural settlement and urban settlement

Rural Settlement Urban Settlement
1. The settlement where the people engaged in primary activities is known as Rural settlement. Urban settlement is the term related to cities and towns where people are primarily engaged in non-agricultural activities
2. The unique feature of rural settlements is the vast, open spaces with green, pollution free environment. The common feature of an urban unit is that they are compact, congested and liable to a large number of populations.

4. Metropolitan and Mega cities

Metropolitan Cities Mega Cities
1. Cities accommodating population between 100 lakhs and 50 lakhs are metropolitan cities. Cities with more than 50 lakhs of population are called Megacities.
2. Example for Metropolitan city is Madura Chennai is an example for Mega cities.

5. Push factors and pull factors

Push factors Pull factors
1. Push factors are those factors which force people to move to new areas to live. Pull factors are those factors that attract migrants to a new location.
2. War, natural disaster, pollution, etc., are the push factors. Fertile land, security, education, etc., are a few pull factors.

6. Primary activities and Secondary activities

Primary activities Secondary activities
1. Primary activities pertain to the extraction of raw materials from the Earth’s surface Secondary activities transform raw materials into finished goods.
2. For example, food gathering, hunting, fishing, agriculture are primary activities. For example, iron and steel industries, automobile manufacturing, etc.,

7. Water pollution and light pollution

Water pollution Light pollution
1. Water pollution is any chemical, physical or biological change in the quality of water that has a harmful effect on any living thing that drinks or uses or lives in it. Light pollution is an unwanted consequence of outdoor lighting and includes such effects as sky glow, light trespass and glare.
2. The water bodies including ponds, lakes, rivers, ground water and oceans are contaminated by the chemical wastes from industries, domestic wastes and sewage etc.  It is caused by street lights, parking lot lights, flood lights, signs, sports field lighting, decorative and landscape lights.

V. Give reasons for the following: 

1. Reforestation is encouraged throughout the world.

  • Cutting of trees results in many effects like floods and droughts, loss of soil fertility, air pollution, global warming, spread of deserts, etc.,
  • To avoid the entire above, reforestation is encouraged throughout the world. It involves the replanting or regeneration of areas of forest.

2. Acid rain destroys the ecosystem.

  • Acid rain contains the sulfur and nitrogen acids. They can cause damage to natural environments including forests and freshwater lakes.
  • Acid rain has many ecological effects. Its impact is heavy
  • on lakes, streams, wetlands, and other aquatic environments.

3. The economy of the quaternary sector is called knowledge economy.

  • The activities related to Research and Development, as well as knowledge are called Quaternary activities.
  • For example, Services like consultation, education and banking.
  • So, the economy of the quaternary sector is also called as Knowledge economy.

4. Population growth has to be brought under control.

  • Population growth leads to unemployment problem, illiteracy, poverty and exploitation of natural resources.
  • It affects the standard of living and the government cannot provide the basic needs to its own people.
  • So, population growth has to be brought under control.

5. Sustainable development growth has been set to protect the planet.

  • Humans on earth are facing many problems, such as pollution, climatic changes, poverty, war and uneven distribution of resources.
  • These problems directly affect the survival of mankind. Therefore to sustain mankind and the planet, we have to educate people about the sustainable development.

VI. Answer in a paragraph:

1. Explain the factors affecting the distribution of population.

Population distribution refers to the way in which people are spread out across the earth’s surface. The world population is not uniformly distributed due to the following factors –

Physical Factors:

Physical factors include temperature, rainfall, soil, relief, water and natural vegetation, distribution of minerals and availability of energy resources.

Historical Factors:

Regions with historical importance like river valleys, centres of war and constant invasion areas fall under historical factors responsible for population distribution

Economic Factors:

Educational institutions, employment opportunities, manufacturing industries, luxurious amenities, trade and commerce and other facilities encourage dense population in an area.

2. Describe the patterns of rural settlement with neat diagrams.

People are engaged in primary activities like agriculture, forestry, mining and fishery is known as a rural settlement. Most of the world’s settlements are rural, that are mostly stable and permanent.

Patterns of rural settlements:

i) Rectangular pattern:

Rectangular pattern of settlements are found in plain areas or valleys. The roads are rectangular and cut each other at right angles.

ii) Linear pattern

In a linear pattern, the houses are located along a road, railway line and along the edge of the river valley or along a levee.

iii) Circular or semicircular pattern

The pattern of settlement that is found around the lakes, ponds and sea coasts are called circular or semi circular pattern.

iv) Star like pattern

Where several metalled or
unmetalled roads converge, star shaped settlements develop. In the star shaped settlements, houses are spread out along the sides of roads in all directions.

v) Triangular pattern

Triangular patterns of rural settlement generally develop at the confluence of rivers.

vi) T-Shaped, Y-Shaped, Cross-Shaped or Cruciform settlements:

T-shaped settlements develop at tri-junctions of the roads (T), while Y-shaped settlements emerge as the places where two roads converge with the third one. Cruciform settlements develop on the cross-roads which extend in all four directions,which extend in all four directions.

vii) Linear pattern

The arrangement of roads is almost circular which ends at the central location or nucleus of the settlement around the house of the main landlord of the village or around a mosque, temple or church.


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