NCERT Solutions for Class 10 Science Chapter 15 – Our Environment

NCERT Solutions for Class 10 Science Chapter 15 – Our Environment, contains solutions to various questions in Exercises for Chapter 15. Our Environment Class 10 NCERT Solutions have been explained in a simple and easy to understand manner. We are providing NCERT Solutions for Class 10 all subjects which can be accessed by clicking here.

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NCERT Solutions for Class 10 Science Chapter 15 – Our Environment – NCERT Exercises

NCERT Solutions for Class 10 Science Chapter 15 – Our Environment, Exercises includes all in text and exercise solved questions which helps you to understand the topic covered in Chapter 15 Our Environment Class 10, in a better manner to help you to score good marks in your examinations.

NCERT Solutions for Class 10 Science Chapter 15 – Intext Questions – Page 260

1. What are trophic levels? Give an example of a food chain and state the different trophic levels in it.

Answer:

In a food chain, the transfer of food and energy takes across various levels of the food chain. These levels are called trophic levels.

An example of the food chain is:

Here, plant represents first trophic level, deer represents second trophic level, and tiger represents third trophic level.

2. What is the role of decomposers in the ecosystem?

Answer:

Decomposers in our ecosystem play the key roles of:

  • Decomposing dead remains of plants and animals.
  • Recycling of nutrients and making soil fertile.
  • Making space for generation of new organisms.

Intext Questions – Page 262

1. Why are some substances biodegradable and some non-biodegradable?

Answer:

Some substances are biodegradable and some are non-biodegradable because microorganisms like bacteria and decomposers like saprophytes can only act on natural resources to break them down and decompose. Hence, they are said to be biodegradable. Man made articles like plastic and other such elements are non-biodegradable.

2. Give any two ways in which biodegradable substances would affect the environment.

Answer:

Two ways in which biodegradable substances would affect the environment are:

  1. They can be easily decomposed, so they return to soil making it fertile affecting the environment in a positive way.
  2. During decomposition, they produce very foul smell and act as bed for various disease carrying organisms such as flies and mosquitoes. This way, they affect the environment in a harmful way.




3. Give any two ways in which non-biodegradable substances would affect the environment.

Answer:

Two ways in which non-biodegradable substances would affect the environment are:

  1. They do not decompose easily, polluting the environment for a very long time.
  2. They can end up in many food chains and produce harmful effects upon consumption.

NCERT Solutions for Class 10 Science Chapter 15 – Intext Questions – Page 264

1. What is ozone and how does it affect any ecosystem?

Answer:

Ozone is an allotrope of oxygen formed by combining three atoms of oxygen. It is found in the upper layers of the atmosphere and is denoted by the formula O3. It protects our ecosystem from the harmful ultraviolet rays of the sun. Such rays can damage many organisms and  lead to diseases like skin cancer. The following reaction undergoes in the upper layers of the environment:

2. How can you help in reducing the problem of waste disposal? Give any two methods.

Answer:

We can reduce the problem of waste disposal by reducing the usage of things itself. We can also recycle and reuse the things that we buy.

Decomposing waste materials and using easily degradable items in our day to day life can also reduce the problem of waste disposal by many folds.

NCERT Solutions for Class 10 Science Chapter 15 – NCERT Exercise – Page 264

1. Which of the following groups contain only biodegradable items?

(a) Grass, flowers and leather

(b) Grass, wood and plastic

(c) Fruit-peels, cake and lime-juice

(d) Cake, wood and grass

Answer:

(a) Grass, flowers and leather, (c ) Fruit-peels, cake and lime-juice, and (d) Cake, wood and grass

2. Which of the following constitute a food-chain?

(a) Grass, wheat and mango

(b) Grass, goat and human

(c) Goat, cow and elephant

(d) Grass, fish and goat

Answer:

(b) Grass, goat and human

3. Which of the following are environment-friendly practices?

(a) Carrying cloth-bags to put purchases in while shopping

(b) Switching off unnecessary lights and fans

(c) Walking to school instead of getting your mother to drop you on her scooter

(d) All of the above

Answer:

(d) All the above

4. What will happen if we kill all the organisms in one trophic level?

Answer:

If we kill all the organisms in one trophic level, the transfer of energy after that trophic level will stop. All the higher organisms will have nothing to eat and will ultimately starve to extinction.

On the other hand, extinction of all the organisms of a higher trophic level will result in tremendous expansion of the population of organisms on lower trophic level and this will cause an imbalance in our ecosystem.




5. Will the impact of removing all the organisms in a trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?

Answer:

Yes, the impact of removing all the organisms in a tropic level will be different for different trophic levels.

No, the removal of organisms at any level would upset the whole ecosystem as the food chain is disturbed as all of the organisms of higher trophic levels are dependent on organisms of lower trophic levels for food.

6. What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?

Answer:

Biological magnification is the progressive accumulation in the concentration of non-biodegradable wastes in the food chain with increasing trophic levels.

Yes, the levels of this magnification are different at different levels of the ecosystem. It will be least in primary levels and maximum in last trophic levels.

7. What are the problems caused by the non-biodegradable wastes that we generate?

Answer:

Non-biodegradable wastes can affect the environment in various ways:

  • They remain in environment for a very long time as they are hard to decompose.
  • Accumulation of large number of non-biodegradable wastes has led to problem in dumping them safely.
  • Many non-biodegradable wastes which are harmful for organisms mix in sources like soil and water and in-evidently become the part of our food chain causing biological magnification.
  • They also affect the fertility of the soil and quality of water and air.

8. If all the waste we generate is biodegradable, will this have no impact on the environment?

Answer:

No, if all the waste we generate is biodegradable, it can have various harmful effects on the environment. Some of them are:

  • Biodegradable wastes are decomposed by bacteria and other microorganisms. These microorganisms can be harmful for the environment. Increase in their number will also increase their need of oxygen, making the environment oxygen deficient.
  • The decomposition of these wastes takes some time. During this process, it can become a bed for a number of disease causing organisms like flies and mosquitoes.
  • Many pungent and harmful gases are released in the process of degradation. These can be harmful to humans as well as environment.

9. Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?

Answer:

The ozone layer acts as a protective shield against the harmful UV rays of the sun. These UV rays can damage the cells of many organisms, destroy planktons and decomposers, and can cause diseases like skin cancer. Hence, damage to ozone layer is a cause for concern.

Most of the damage to the ozone layers is caused by chlorofluorocarbons (CFCs). These compounds are found in devices like refrigerator and AC.

In order to decrease the usage of CFCs, many nations signed an agreement to obey the directions of UNEP (United Nations Environment Programme).

Topics Covered in Our Environment Class 10 Science

  • What Happens When We Add Our Waste To The Environment?
  • Ecosystem — What Are Its Components?
  • Ozone Layer and Waste Disposal
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