Important Questions for CBSE Class 7 Science Our Environment Chapter 1 - Environment

Very Short Answer Questions:   1 Mark

1. Fill in the blanks:

(i) The _____________is the layer of earth which surrounds the earth.

Ans: The atmosphere is the layer of earth which surrounds the earth.

(ii) The atmosphere is held by the force of __________.

Ans: The atmosphere is held by the force of gravity.

(iii) The topmost layer of the earth is ___________.

Ans: The topmost layer of the earth is the lithosphere.

(iv) Biotic components conclusively made an __________.

Ans: Biotic components conclusively made an ecosystem.

2. State True and False:

(i) World Environment Day is celebrated in June in ${5^{{\text{th}}}}$ June.

Ans: True

(ii) In the Barter system people used a method of exchange.

Ans: True

(iii) Hydrosphere is the domain of water.

Ans: True

(iv) Biotic Consists are the dead organisms.

Ans: False

3. Match the Following:

Ans: 

4. Choose the Correct Option:

(i) ___________is a human made environment.

(a) Sea

(b) Road

(c) Mountain

(d) None of the above

Ans: (b) Road

(ii) ___________is not a natural ecosystem.

(a) Aquarium

(b) Forest

(c) Desert

(d) None of the above

Ans: (a) Aquarium

5. Define the Following:

(i) Environner

Ans: Environner is known as the neighbourhood.

(ii) Four spheres of earth

Ans: Four spheres of the earth are as follows: Atmosphere, Hydrosphere, 

Lithosphere, Biosphere.

Short Answer Questions: 2 Marks

6. Define ecosystem.

Ans: The interdependence between living beings and their environment is known as an ecosystem.

7. What is Natural Environment?

Ans:  The natural environment comprises biotic components like living beings and abiotic organisms like air and water etc.

8. What are the Components of the Environment?

Ans: Following are the components of the environment:

• Biotic components: This includes humans and all living beings.

• Abiotic components: This includes all non-living components. These components can be natural i.e., air, water, soil, wind, sunlight, etc. or they can be manmade, i.e., roads, buildings, cars, boats, etc. 

9. Define the Biosphere.

Ans: The part of the earth where all the living beings exist and obtain their nutrition and complete their life cycle is called the biosphere.

10. Define Lithosphere.

Ans: Lithosphere is the top segment of earth’s mantle i.e. brittle crust of the earth and it is made up of rocks and minerals.

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Short Answer Questions: 3 Marks

11. Why Do Animals and Plants Depend on Each Other?

Ans: The interdependence between the plants and animals is for the food as well as the air they breathe in. Plants utilise carbon dioxide, exhaled by the animals for the formation of food and on the other hand, oxygen is used by animals which are released by plants during food formation, for breathing purposes.

12. Why Do Men Modify the Environment?

Ans: Following are the reasons for the modification of the environment by men:

• The environment is modified for the production of more food.

• Surrounding gets changed for the construction of houses and other structures.

• For making the things of daily requirements.

• For Protection from natural events.

13. Can Plants Take Nitrogen Directly from the Air?

Ans: No, plants are not able to take nitrogen directly from the air. The bacteria are responsible for changing the nitrogen in the air to the nitrogenous compound so that they can be consumed by plants easily.

14. What is the Use of the Oxygen in the Air?

Ans: Oxygen is quite essential for the survival of living beings. A human inhales a mixture of gases from the atmosphere but the red blood cells absorb oxygen and the lungs flush out the rest of the air from the body.

15. Define Hydrosphere.

Ans: Hydro refers to water. That sphere of the earth that contains water or its associated elements are known as the hydrosphere.

Long Answer Questions:     5 Marks

16. What is the Environment? Why Do Human Beings Modify Their Environment?

Ans: The surrounding area that provides essential items like air, water, food etc. which is essential for the survival of human life is called an environment. Man modifies his environment because of the following reasons:

• The environment is modified for the production of more food.

• Surrounding gets changed for the construction of houses and other structures.

• For making the things of daily requirements.

• For Protection from natural events.

17. What are the Components of the Environment?

Ans: There are three components of the environment, such as:

• Man-made Component: The environment created by humans is known as a man-made environment. For example, buildings, bridges, industries, roads etc.

• Human Environment: It is created with the presence of different religions, families, caste, political and economic systems etc.

• Natural Environment: It is made up of all the biotic and abiotic components. For example, land, air, water, living beings etc.

18. Explain the Natural Environment.

Ans: The natural environment comprises biotic components like living beings and abiotic organisms like air and water etc. The natural environment is divided into four parts:

• Lithosphere: Lithosphere is the topmost layer of the soil and it is made up of rocks and minerals. In this layer, crops are grown and all other human activities are conducted.

• Hydrosphere: Hydro refers to water. That sphere of the earth that contains water or its associated elements are known as the hydrosphere.

• Atmosphere: Thin layer of gases which surrounds the earth is known as the atmosphere. This layer also protects the earth from harmful gases.

• Biosphere: The region of the earth where land, air, and water interact and become responsible for the survival of living beings are known as the biosphere.

19. Explain the Ecosystem Briefly.

Ans: An ecosystem is a biological community where living organisms interact with their physical environment. The biotic and abiotic components are associated with each other through energy flows and nutrient cycles. The energy gets transferred from one organism to another organism. The plants and animals are also dependent on one other as well as on their immediate neighbourhood.

20. Briefly Explain the Human Environment.

Ans: Earlier it was very easy for the people to adapt themselves according to the environment but over time as the needs increased, they started modifying the environment. The factors responsible for modification are as follows:

• The environment is modified for the production of more food.

• Surrounding gets changed for the construction of houses and other structures.

• For making the things of daily requirements.

• For Protection from natural events.