NCERT Class X Science Class: Chapter –15. Our Environment – Part-4

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Question 19:

The decomposers in an ecosystem

(a) Convert inorganic material, to simpler forms

(b) Convert organic material to inorganic forms

(c) Convert inorganic materials into organic compounds

(d) Do not breakdown organic compounds

Answer: B

Image Decomposers in an ecosystem

Image Decomposers in an Ecosystem

Image Decomposers in an ecosystem

Question 20:

If a grass hopper is eaten by a frog, then the energy transfer will be from

(a) Producer to decomposer

(b) Producer to primary consumer

(c) Primary consumer to secondary consumer

(d) Secondary consumer to primary consumer

Answer: C

Image Primary consumer to secondary consumer

Image Primary Consumer to Secondary Consumer

Image Primary consumer to secondary consumer

Question 21:

Disposable plastic plates should not be used because

(a) They are made of materials with light weight

(b) They are made of toxic materials

(c) They are made of biodegradable materials

(d) They are made of non-biodegradable materials

Answer: D

Short Answer Questions

Question 22:

Why is improper disposal of waste a curse to environment?


Improper disposal of waste a curse to environmental.It is because waste pollutes our environment air, soil, water, and causes of harmful effects on all living organisms.

Question 23:

Write the common food chain of a pond ecosystem.


Phytoplankton’s and aquatic plants → small aquatic animals larvae, insects etc. → fish → bird

Image Common food chain of a pond ecosystem

Image Common Food Chain of a Pond Ecosystem

Image Common food chain of a pond ecosystem

Question 24:

What are the advantages of cloth bags over plastic bags during shopping?


Cloth bags are

(a) Capable of carrying more things

(b) Made of biodegradable material

(c) Do not pollute our environment

(d) Can be reused

Question 25:

Why are crop fields known as artificial ecosystems?


In a crop field, plants do not grow naturally rather most of the plants are grown by humans. An ecosystem is nevertheless present in a crop field, but it is an artificial ecosystem as a major component of the ecosystem comes into origin because of human intervention.

Question 26:

Differentiate between biodegradable and non-biodegradablesubstances. Cite examples.


1. Biodegradable are the one which gets decomposed within very short period. While non biodegradable take longer time.

2. Biodegradable wastes are non pollutants while non biodegradable are pollutants.

3. Biodegradable ones are degraded by living organisms while non biodegradable have no part with living organisms.

4. Biodegradable wastes can be disposed easily but non ones cannot.

5. Biodegradable are organic ones whereas the non ones are artificial mostly polymers

6. Biodegradable can act as soil manures while non ones cannot.

Biodegradable example - fruits, vegetables, plants, animals, etc..

Non biodegradable example - plastics, glasses, etc

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