Here you get the CBSE Class 10 Science chapter 15, Our Environment: NCERT Exemplar Problems and Solutions (Part-II). This part of the chapter includes solutions for Question No. 22 to 30 from the NCERT Exemplar Problems for Class 10 Science Chapter: Our Environment. These questions include only the Short Answer Type Questions framed from various important topics in the chapter. Each question is provided with a detailed explanation.
NCERT Exemplar Solution for CBSE Class 10 Science Chapter: Our Environment (Part-I)
NCERT Exemplar problems are a very good resource for preparing the critical questions like Higher Order Thinking Skill (HOTS) questions. All these questions are very important to prepare for CBSE Class 10 Science Board Examination 2017-2018 as well as other competitive exams.
Find below the NCERT Exemplar problems and their solutions for Class 10 Science Chapter, Our Environment:
Short Answer Type Questions
Question 22. Why is improper disposal of waste a curse to environment?
Answer.
Certain substances when burnt in air releases harmful gases. When these substances dumped in river or sea create water pollution. Some sort of waste materials on dumping inside the ground can make the land infertile.
So, if proper method of waste disposal system is not used then it will contaminate the environment.
Question 23. Write the common food chain of a pond ecosystem.
Answer.
A common food chain of a pond ecosystem is as follows:
Producers (aquatic plants) → Herbivores (Protozoa) → Carnivore (Small fishes) → Large Carnivores (Large Fishes)
Question 24. What are the advantages of cloth bags over plastic bags during shopping?
Answer.
Cloth bags have many advantages over plastic bags, some of them are:
Bags made of clothes can be used again and again by washing or modifying. One can modify these bags in home. Cloth bags are biodegradable and don’t causes pollution.
Question 25. Why are crop fields known as artificial ecosystem?
Answer.
Ecosystems which are made by man are known as artificial ecosystem.
In case of crop fields abiotic and biotic components are selected by humans. The essential process such as sowing seeds, then irrigated and further progress is also kept under observation for getting good yield.
Question 26. Differentiate between biodegradable and non-biodegradable substances. Give examples.
Answer.
Difference between biodegradable and non-biodegradable substances are:
| S. No. | Biodegradable substances | Non-biodegradable substances |
| 1. | Substances that can be broken down into simpler substances by the action of decomposers | Substances that can’t be broken down into simpler substances by the action of decomposers. |
| 2. | These substances do not cause pollution. | These substances cause pollution. |
| 3. | e.g. vegetables, fruits etc. | e.g. polythene, DDT etc. |
Question 27. Suggest one word for each of the following statement/definitions.
(a) The physical and biological world where we live in
(b) Each level of food chain where transfer of energy takes place
(c) The physical factors like temperature, rainfall, wind and soil of an ecosystem
(d) Organisms which depend on the producers either directly or indirectly for food
Answer.
(a) Environment
(b) Trophic level
(c) Abiotic factors
(d) Consumers
Question 28. Explain the role of decomposers in the environment.
Answer.
The microorganisms, comprising bacteria and fungi, break-down the dead remains and waste products of organisms. These microorganisms are the decomposers as they break-down the complex organic substances into simple inorganic substances that go into the soil and are used up once more by the plants.
They act as natural cleaning agent by decomposing dead organisms and biodegradable wastes and helps in replenishment of the soil’s nutrients,
Question 29. Select the mis-matched pair in the following and correct it.
| (a) Bio-magnification | Accumulation of chemicals at the successive trophic levels of a food chain |
| (b) Ecosystem | Biotic components of environment |
| (c) Aquarium | A man-made ecosystem |
| (d) Parasites | Organsims which obtain food from other living organisms |
Answer. (b)
An ecosystem consists of biotic components (living organisms) as well as abiotic components (soil, air, water etc.) of environment.
Question 30. We do not clean ponds or lakes, but an aquarium needs to be cleaned. Why?
Answer.
A pond or a lake forms a natural and complete ecosystem. All the food chain presents in these ecosystems are complete. These ecosystems have plenty of producers, consumers and decomposers.
On the other hand an aquarium is an incomplete artificial ecosystem. An aquarium does not have enough population of decomposers to decompose waste material produced by aquatic animals. Due to this reason aquarium needs to be cleaned frequently.
CBSE Class 10 Science Syllabus 2017-2018
NCERT Solutions for CBSE Class 10 Science
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