6th Std Science Term 3 Solution | Lesson.4 Our Environment

Lesson.4 Our Environment

Our Environment Book Back Answer - 2021

Lesson.4 Our Environment

I. Choose the correct answer:

1. Identify the fresh water ecosystem. 

  1. Pond
  2. Lake
  3. River
  4. All of them

Ans : All of them

2. Producers are_______________

  1. Animals
  2. Birds
  3. Plants
  4. Snakes

Ans :  Plants

3. It is a biodegradable waste

  1. Plastic
  2. Coconut Shell
  3. Glass
  4. Aluminium

Ans : Coconut Shell

4. It is an undesirable change that occurs in air and water

  1. Recycling
  2. Reuse
  3. Pollution
  4. Reduce

Ans : Pollution

5. Usage of chemical pesticides and fertilisers causes ________ pollution.

  1. Air pollution
  2. Water pollution
  3. Noise pollution
  4. None of the above

Ans : None of the above

II. Fill in the Blanks 

1. Primary consumers that eat plants are called __________

Ans : Herbivore

2. Temperature, light and wind are ________ factors

Ans : Physical

3.  ______ is the process of converting waste materials into new materials.

Ans : Recycle

4. Water pollution can spread __________ and chemicals.

Ans : disease

5. The 3R’s are Reduce, __________ and Recycle.

Ans : Reuse

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

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

Ans : True

2. Bacteria and fungi are called decomposers.

Ans : True

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

Ans : False

Cu. An. : Human and animal wastes are examples of biodegradable waste.

4. Excessive use of pesticides leads to air pollution.

Ans : False

Cu. An. : Excessive use of pesticides leads to Land pollution.

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

Ans : True

IV. Match the Following

1. Biotic factorTerrestrial Ecosystem
2. SewageLand pollution
3. FertilizersAir pollution
4. DesertWater Pollution
5. SmokeAnimals
Ans : 1 – E, 2 – D, 3 – B, 4 – A, 5 – C

V. Arrange the following statements in correct sequence

1. Rabbit Carrot Eagle Snake

Ans : Carrot Rabbit Snake Eagle

2. Human Insect Algae Fish

Ans : Algae Insect Fish Human

VI. Give very short answer 

1. Define ecosystem

Ecosystem is a community of living and non-living things that work together. Each part of an ecosystem has a role to play. Any changes in the environment such as increased temperature or heavy rains, can have a big impact on an ecosystem.

2. What are the two types of ecosystems?

  • Natural ecosystem
  • Artificial ecosystem

3. Write any two things that can be recycled

The process by which waste materials are used to make new products is called recycling.(e.g) Using old clothes to make paper and melting some plastics to make floor mats, plastic boards and hose pipes.

4. What are the types of pollution

There are four major kinds of pollution:

  • Air pollution
  • Water pollution
  • Land (soil) pollution
  • Noise pollution

5. Give one example of a food chain in an aquatic ecosystem?

E.g. Food chain in an aquatic (lake) ecosystem

Our Environment Book Back Answer - 2021

Aquatic Plant —–> Aquatic Insect  —–> Larva —–> Fish

6. Name some pollutants

Sewage, Industrial effluents,solid waste from our own homes like plastics and broken electronics ,oil, petrol, coal and natural gas etc.,

7. Name some pollutants

a. Loud Speaker

  • Loud Speaker – Noise pollution

b. Plastic

  • Plastic – Land pollution

VIII. Give short answer

1. How can we reduce water pollution?

The term ‘Biodegradable’ is used for those things that can be easily decomposed by natural agents like water, oxygen, ultraviolet rays of the sun, microorganisms, etc.

2. How can we reduce water pollution?

  • Do not pour leftover oil, old medicines or waste down the drain or into the toilet.
  • Reduce the use of chemical pesticides and fertilizers to grow crops.
  • Use waste water for garden in home.
  • Do not litter or dump waste – always use a waste bin.

3. Write the importance of the food chain.

In any ecosystem there is a chain like relationship between the organisms that live there. This sequence of who eats whom in an ecosystem is called as food chain. It describes how organisms get energy and nutrients by eating other organisms.

IX. Answer in detail

1. Give two examples of how you can avoid or reduce waste?

1. Avoid :

  • Avoid the usage of unwanted materials which create more debris.
  • Before you buy anything, think that “Do I really need it?”
  • (e.g) Avoid buying packaged foods. Refuse to buy use and throw plastic products.

2. Reduce

  • We can reduce the waste by using durable goods that last longer instead of things that are used once and thrown away.
  • (e.g) Write on both sides of papers. Instead of unnecessary printing, use electronic facilities. Share newspapers, magazines and other things with others.

2. Write a short note on noise pollution.

Noise pollution affects the environment. We all like a quiet and peaceful place since unpleasant or loud sounds disturb us. Loud music, the sounds of motor vehicles, fire works and machines cause noise pollution. Continuous noise disturbs our sleep and does not let us to study. Noise pollution has been directly linked to stress and health impacts such as high blood pressure and hearing loss. Loud noise or even loud music can damage our ears. Noise pollution also disturb animals. Birds have to communicate (talk) louder so that, they can hear each other in noisy areas. Even underwater noise pollution from ships, can make whales lose their way as they use sounds to navigate.

Our Environment Book Back Answer - 2021

How do we reduce noise pollution?

  • Turn off your electronics when you do not use them.
  • Lower the volume when you watch TV or listen to music.
  • Remind drivers not to use the horn too much.
  • Avoid fireworks.
  • Speak, do not shout (try to set an example).


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