29 Apr 2022

Samacheer kalvi 6th Science Term 3 Unit 4 Answers

Samacheer Kalvi 6th Science Term 3 Unit 4 Book Back Question and Answers/Solutions:

Samacheer Kalvi 6th Standard New Science Book Back 1 Mark and 2 Mark Question & Answers PDF uploaded and available below. Class 6 New Syllabus 2021 to 2022 Book Back Question & Answer solutions available for both English and Tamil Medium. Class 6 Science  Book Term 3 Unit 4 Our Environment Answers/Solutions are provided on this page. 6th Std Science Book is of 1st Term, 2nd Term consists of 7 units and 3rd Term consists of 6 units. All Units/Chapters of Term 1st, 2nd, 3rd Social Book Back One, and Two Mark Solutions are given below.

Check Unit wise and  6th New Science Book Back Question and Answers Guide/Solutions PDF format for Free Download. English, Tamil, Maths, Science, and Social Science Book Back Questions and Answers available in PDF. Check Science Book Back Solutions below. See below for the Samacheer Kalvi 6th Science Term 3  Unit 4 Book Back Answers PDF:

Samacheer Kalvi 6th Science Book Back Chapter 4 Term 3 Answers/Solutions Guide PDF:

Science Subject 1 Mark and 2 Mark Solutions Guide PDF available below. Click the Download option to download the book back 1 Mark & 2 Mark questions and answers. Take the printout and use it for exam purposes.

6th Science – Term 1 Unit 4

Our Environment

I. Choose the appropriate answer:

1. Identify the fresh water 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 Very Short Answer:

1. Define ecosystem.
An ecosystem is a community of living or biotic and non-living or a 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 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.

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