Class VII Social Science Ch-1 (D A V Publication)

         

                                    

                                                SOCIAL SCIENCE

                   Class VII (DAV Publication)

 

             Chapter-Wise Questions and answers of

                  Ch- 1 (Components of Environment)

B. Give the single term for each of the following sentences.

Q1. A situation or condition in which an organism lives           Biosphere

Q2. The only planet in our solar system where life exist.          Earth

Q3. The uppermost part of the lithosphere which is rich in silica and aluminium                                                                                              Sial

Q4. The sphere of air that envelops the earth.                       Atmosphere

Q5. The mass of water on the earth’s surface                              71%

C. Match the following:

1. Physical environment includes                   -            (c) Non-living things

2. It iis the most dynamic in nature               -             (a) Atmosphere

3. A narrow zone supporting life                    -             (d) Biosphere

4. They are capable of modifying environment   -     (b) Human Beings

5. Rocks rich in Silica and Magnesium          -               (e) Sima

D. Answer the following questions in brief.

Q1. Name the major components of the environment.

Answer- Major components of the environment are:

(i)               Physical Environment

(ii)            Biological Environment

Q2. What is meant by Sima and Sial?

Answer- The uppermost part of the lithosphere which is composed of rocks rich in Silica and Magnesium is called Sima while the rock which is rich in Silica and Aluminium is called Sial.

Q3. Mention the distribution of water in the Northern and Southern hemispheres.

Answer- 43% of the total area covered by water lies in the northern hemisphere whereas the remaining 57% lies in the southern hemisphere.

Q4. Give the literal meaning of four spheres of environment.

Answer- Lithosphere- “Sphere of rocks”

Name of Spheres	Literal Meanings
(i)               Lithosphere                      →                  “Spheres of rocks” (ii)            Atmosphere                     →                  “Sphere of Air” (iii)          Hydrosphere                    →                  “Sphere of Water” (iv)          Biosphere                         →                   “Sphere of Life”

     

Q5. What is the atmosphere composed of?

Answer- Atmosphere is composed of a mixture of gases which forms an envelope around the earth. It is a gaseous envelope extending about 1600 km above the surface of the earth. Of the total mass of the atmosphere, 99% exists within 32km of height from the surface of the earth.  

e. answer the following questions.     

Q1. Differentiate between the physical and biological environment.

Answer-

Physical Environment	Biological Environment
(i)               It is the first part of the environment which composed of all non-living things. (ii)            The examples of physical environment are land, water and air. (iii)          Sudden changes can’t be observed. (iv)          Some of the developments can’t be visualised through our senses. (v)            All resources are natural.	(i)               It is the second part of the environment which is composed of all living things. (ii)            The examples of biological environment are plants, animals and human beings. (iii)          Sudden changes can be observed. (iv)          Almost all development can be visualised through our senses. (v)            Some of are man-made.

 Q2. Why is the earth called the “Blue Planet”?

Answer- 71% surface of the earth is covered with water while only 29% surface of the earth is covered with land. When we see the earth from the space, it appears blue due to abundance of water. So the earth is called “Blue Planet”.    

Q3. Define Biosphere. Why is it important for us?

Answer- The combination of Lithosphere, Atmosphere and Hydrosphere is called Biosphere. It is the sphere of life. Life can exist on the land, in the air and in the water. All life supporting systems are available in this sphere. Human Being is found in this sphere who has the availability to change all the spheres. That is why biosphere is important for us.

Q4. Explain with the help of an example how physical and biological components of the environment are interdependent.

Answer- Physical and Biological components of environment are interdependent. When any change takes place in physical environment then biological environment are also changed. For example, the development of soil takes years together and cannot be visualised through our senses. When the fertility of this soil is decreased, the production of food grains will also be decreased and the biological environment is greatly influenced due to the scarcity of food grains.     

Q5. Explain two ways in which human beings are disturbing the natural environment. 

Answer- Industrialisation is the first way through which human beings are disturbing the natural environment. Different types of poisonous gases mix up in the air which are causing different types of environmental pollution. Thus our natural resource air is being polluted by human beings.

 

                       Deforestation is the second way by which human being is disturbing the natural environment. Owing to the reckless cutting of trees by humans different types of environmental pollutions are being caused. By disturbing the natural environment humans are causing harms to themselves.