29 Apr 2022

Samacheer kalvi 6th Science Term 3 Unit 4 Answers

Samacheer Kalvi 6th Science Term 3 Unit 4 Book Back Questions and Answers:

Samacheer Kalvi 6th Standard Science Book Back 1 Mark and 2 Mark Question & Answers uploaded online and available PDF for free download. Class 6th New Syllabus Science Term 3 book back question & answer solutions guide available below for English Medium. Class sixth Std Science English Medium Term 3 Unit 4 Our Environment book back answers are given below. Students looking for class 6th Term III Unit 4 Questions and Answers can check below.

We also provide class 6th other units Book Back One and Two Mark Solutions Guide on our site. Students looking for a new syllabus 6th standard Science Term 3 Unit 4 Our Environment Book Back Questions with Answer PDF:

For all three-term of 6th standard Science Book Back Answers English Medium – Samacheer kalvi 6th Science Book Back Answers

Samacheer Kalvi 6th Science Book Back Chapter 4 Term 3 Solution Guide PDF:

TN State Board Class 6th Science Subject Term 3 Unit 4 one mark and two mark solutions guide PDF available below.

6th Science – Term 1

Unit 4 – Our Environment

I. Choose the appropriate answer:

1. Identify the freshwater ecosystem.
(a) Pond
(b) Lake
(c) River
(d) All of them
(d) All of them

2. Producers are
a. Animals
b. Birds
c. Plants
d. Snakes
c. Plants

3. It is a biodegradable waste
(a) Plastic
(b) Coconut Shell
(c) Glass
(d) Aluminium
(b) Coconut shell

4. It is an undesirable change that occurs in air and water.
a. Recycling
b. Reuse
c. Pollution
d. Reduce
c. Pollution

5. Usages of chemical pesticides and fertilisers causes pollution.
(a) Air pollution
(b) Water pollution
(c) Noise pollution
(d) None of the above
(b) Water pollution

II. Fill in the blanks :

  1. Primary consumers that eat plants are called _______
  2. Temperature, light and wind are _______ factors.
  3. _______ is the process of converting waste materials into new materials.
  4. Water pollution can spread _______ and chemicals.
  5. The 3R’s are Reduce, _______ and Recycle.


  1. Herbivores
  2. Physical
  3. Recycling
  4. Diseases
  5. Reuse

III. True or False. If False, give the correct statement:

1. The Pacific ocean is an example of an aquatic ecosystem.

2. Bacteria and fungi are called decomposers.

3. Human and animal wastes are examples of non-biodegradable waste.
False. Human and animal wastes are examples of biodegradable waste.

4. Excessive use of pesticides leads to air pollution.
False. Excessive use of pestides leads to water pollution.

5. In schools, waste management rules say that we should separate waste in two categories.

IV. Match the following :

  1. Biotic factor – Terrestrial Ecosystem
  2. Sewage – Land pollution
  3. Fertilizers – Air pollution
  4. Desert – Water Pollution
  5. Smoke – Animals


1 – v; 2 – iv; 3- ii; 4 – i; 5 – iii

V. Arrange the following in a correct sequence and form a food chain

1. Rabbit → Carrot → Eagle → Snake
Carrot → Rabbit → Snake → Eagle

2. Human → Insect → Algae → Fish
Algae → Insect → Fish → Human

VI. Give a Very Short Answer:

1. Define ecosystem.
An ecosystem is a community of living or biotic and non-living or biotic things that work together.

2. What are the two types of ecosystems?
Types of ecosystems :

  1. Natural ecosystem
  2. Artificial ecosystem

3. Write any two things that can be recycled.
Examples :

  1. Old clothes
  2. Plastics

4. What are the types of pollution?
There are four major kinds of pollution :

  1. Air Pollution.
  2. Water Pollution.
  3. Land (Soil) Pollution.
  4. Noise Pollution.

5. Give one example of a food chain in an aquatic ecosystem.
Food chain in aquatic ecosystem.
Aquatic plant → Aquatic insect → Larva → Fish.

6. Name some pollutants.

  1. Toxic gases and fine particles from burning fossil fuels, chemicals released from factories.
  2. Sewage, industrial effluents, pesticides and fertilizers
  3. Plastics and electronics are land pollutants.

7. What are the pollutions caused by the objects given below?
a. Loud Speaker
b. Plastic
a. Loud Speaker – Noise Pollution.
b. Plastic – Land Pollution.

VII. Give a Short Answer:

1. What is biodegradable waste?
The term ‘‘Biodegradable” is used for those things that can be easily decomposed by natural agents like water, oxygen, ultraviolet rays of sun and microorganisms etc.

2. How can we reduce water pollution?

  1. Do not pour leftover oil, old medicines or waste down the drain or into the toilet.
  2. Reduce the use of chemical pesticides and fertilizers to grow crops.
  3. Reduce the use of detergents and bleach to wash clothes.
  4. Do not litter or dump waste always use a waste bin.

3. Write the importance of the food chain.
Importance of food chain

  1. Learning food chain help us to understand the feeding relationship and interaction between organisms in any ecosystem.
  2. Understanding the food chain also helps us to appreciate the energy flow and nutrient circulation in an ecosystem.
  3. This is important because pollution impacts the ecosystem. The food chain can be used to understand the movement of toxic substances and their impacts.

Other Important links for Class 6th Book Back Answers:

Tamil Nadu Class 6th Standard Book Back Guide PDF, Click the link – 6th Book Back Questions & Answers PDF

For all three-term of 6th standard Science Book Back Answers English Medium – Samacheer kalvi 6th Science Book Back Answers English Medium 

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