Class 10 Science Chapter 15 Our Environment

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Class 10 Science Chapter 15 Our Environment The answer to each chapter is provided in the list so that you can easily browse throughout different chapters NCERT Class 10 Science Chapter 15 Our Environment and select need one.

Class 10 Science Chapter 15 Our Environment

Also, you can read the SCERT book online in these sections Solutions by Expert Teachers as per SCERT (CBSE) Book guidelines. These solutions are part of SCERT All Subject Solutions. Here we have given Assam Board Class 10 Science Chapter 15 Our Environment Solutions for All Subjects, You can practice these here…


Q.1. Define with examples. 

( i ) Biodegradable waste.

( ii ) Non biodegradable waste.

Ans :- ( i ) Those waste materials which can be broken down to non poisonous substances in nature in due course of time by the action of micro organisms like certain bacteria are called biodegradable waste. Cattle dung and compost are common examples of biodegradable wastes. 

( ii ) The waste material which seen not be broken down into non-poisonous or harmless substances in nature are called non- biodegradable wastes. The examples of non-biodegradable wastes are D.D.T, Plastics etc. 

Q.2. Define ecosystem. Given example? 

Ans :- An ecosystem is a self-contained unit of living things like as plants, animals and decomposers and their nonliving environment like as soil, air and water. An ecosystem needs only the input of sunlight energy for its functioning. The example of ecosystems are :- a grassland, a forest, a desert, a mountain etc. 

Q.3. Which are the abiotic component of an ecosystem? 

Ans :- The abiotic components of an ecosystem include the physical environment like soil, water and air along with the inorganic substances like carbon di oxide, nitrogen, oxygen water, phosphorus, sulphur, sodium etc. present in then. The physical factors or climatic factors like light, temperature, pressure and humidity are also considered abiotic components of the ecosystem. 

Q.4. What is biotic components of ecosystem? 

Ans :- The biotic component of an eco system is a community of organisms like plants and animals which is made t inter dependent populations. The biotic community of an ecosystem includes three types of organisms. 

( i )  Producer organisms. 

( ii ) Consumer organism. 

( iii ) Decomposer organism. 

Q.5. How an ecosystem functions as a self-sufficient or independent unit in nature?

Ans :- From the nutrient pool of the earth, carbon dioxide and water are absorbed by the producer organisms like as green plants. With the help of sunlight energy, the producer organisms convert these inorganic substances into organic compounds like carbohydrates which act as a food. Thus producers trap the solar energy and then provide the basic food or energy for all other life forms in the ecosystem. 

The consumers derive their energy needs, directly or indirectly, from producers. When the producers and consumers die, then the decomposer organisms act on their dead bodies to return the various elements back to the nutrient pool. Thus an ecosystem involves input of energy and matter which are exchanged between living and nonliving components in a cyclic process. 

Q.6. Define producers. Give example. 

Ans :- Producers are the organisms which can prepare their own food from simple in organic substances like carbon dioxide and water by using sunlight energy in the presence of chlorophyll, The examples of producers are green plants and certain blue-green algae. 

Q.7. Define consumers. Give example. 

Ans :- Those organisms which consume food prepared by producers are called consumers. 

For example :- All the animals are consumers. 

Q.8. Define decomposers. Give examples. 

Ans :- The micro-organisms which break down the complex organic compounds present in dead organisms like dead plants and animals and their products like faces, urine, etc. into simpler substances are called decomposers. 

Examples : Certain bacteria and fungi. 

Q.9. Write two important role of decomposers. 

Ans :- ( i ) The decomposers help in decomposing the dead bodies of plants and animals, and hence act as cleansing agents of environment. 

(ii) The decomposer organisms help in recycling the materials in the ecosystem so that the process of life may go on and on like an unending chain. 

Q.10. What is food chain? 

Ans :- The sequence of living organisms in a community kin which one organism consumes another organism to transfer food energy is called a food chain. 

Q.11. Define food web. 

Ans :- The interconnected food chains operating in an ecosystem which establish a network of relationships between various species, is called a food web. 

Q.12. What do you mean by the term trophic level? 

Ans :- The various steps in a food chain at which the transfer of food takes place are called trophic levels. Inface, in a food chain, each step representing an organism form a trophic level. In most simple terms ‘trophic level’ means ‘feeding level’ of the organism. 

Q.13. Define Ten Per Cent Law. 

Ans :- According to ten per cent law, only 10 per cent of the entering a particular trophic level of organisms is available for transfer to the next higher trophic level. 

Q.14. Every household produces a lot of material A daily. In one of the methods of disposal B, material A is burned at a very high temperature of about 1000°C in a structure called C. During this process, the organic matter present is removed as D and E whereas F is left energy behind. 

( a ) What is material A? 

( b ) Name the method of disposal B. 

( c ) What is the structure C known as? 

( d ) What are ( i ) D ( ii ) E and ( iii ) F? 

( e ) This method is especially suitable for the disposal of materials produced by certain institutions. Name such institutions. 

Ans :- ( a ) Garbage.

          ( b ) Incineration.

         ( c ) Incinerator.

         ( d ) ( i )  Carbon di oxide.

                ( ii ) Water.

                ( iii ) Ash.

          ( e ) Hospitals.

Q.15. The gas A is used by most of the animals to obtain energy from food by the process of respiration. When A is gas acted upon by radiation X, it gets converted in to another B which is an allotrope of A but poisonous when inhaled. B forms a kind of layer C in the upper atmosphere which absorbs radiations X coming from a source Y and prevent them from reaching the earth. Some chemicals Z released from the various devices on the earth are destroying the layer C slowly. In fact, a hole has already been formed in layer C over the area D of the earth. 

( a ) What are gases 

( i )  A 

( ii ) B? Write their molecular formula .

( b ) Name the layer  C.  

( c ) What are ( i ) X  

                         ( ii ) Y

                         ( iii ) Z ?

( d ) Name the area D 

( e ) Name any two human ailments which may be caused by ‘X 

Ans :- ( a ) ( i ) Oxygen, O₂ 

                 ( ii ) Ozone, Oz 

          ( b ) Ozone layer.

          ( c ) ( i ) Ultraviolet radiations.

                 ( ii ) Sun.

                 ( iii ) Chlorofluorocarbon.

          ( d ) Antarctica.

          ( e ) Skin cancer; cataract. 

Q.16. At which trophic level a person is feeding when he is eating : 

( a ) Roasted chicken.

( b ) Bread.

( c ) Eggs.

( d ) Apple.

( e ) Fish.

Ans :- ( a ) 3rd trophic level.

          ( b ) 2nd trophic level.

          ( c ) 3rd trophic level.

          ( d ) 2nd trophic level.

          ( e ) 4th trophic level. 

Q.17. What are the nature’s cleansing agent? 

Ans :- Natural cleansing agents are – microorganisms, bacteria, ln algae.

Q.18. Give examples of herbivores, carnivores, omnivores and decomposers. 

Ans :- Herbivores :- Camel, Deer, Cow, Rabbit. 

          Carnivores :- Lion, Tiger, Vultures. 

          Omnivores :- Monkey, Human. 

          Decomposers :- Insects, Bacteria, Fungi. 

Q.19. What happens when an organism dies? 

Ans :- The decomposers in the soil or water, act upon the dead organisms and breakdown the complex organic substances into simple inorganic compounds which go into the soil and are used up once more by the plants. 

Q.20. Write one or two words for each of the following statements. 

( a ) Each level of food chain where transfer of energy takes place. 

( b ) The physical factors like temperature, rainfall, light, soil, air and water of an ecosystem. 

( c ) Organisms which depend on the producers for food either directly or indirectly. 

( d ) She physical and biological world where we live in. 

( e ) Self contained unit of living things and their nonliving environment needing only sunlight for its functioning. 

Ans :- ( a ) Trophic level.

          ( b ) Abiotic components.

          ( c ) Consumers.

          ( d ) Environment.

          ( e ) Ecosystem.

Q.21. Fill in the blanks : 

( i ) Enzymes are ——— in their action. 

( ii ) Substances that are broken down by biological processes are said to be ————.

( iii ) Substances that are not broken down by biological process are said to be ———–.

( iv ) Gardens and crop fields are examples of————–. 

( v ) The decomposers comprising microorganisms like—————.

( vi ) Every food chain starts from —————. 

( vii ) The flow of energy is always ———— in food chains.

( viii ) The plants trap ————- energy and convert it into ———– energy. 

( ix ) In an ecological pyramid, the base represents————- love. 

( x ) In nature, all green plants are ————- whereas animals are consumers.

Ans :- ( i ) Specific.

          ( ii ) Biodegradable.

          ( ii ) Non-biodegradable. 

          ( iv ) Artificial ecosystem 

          ( v ) Bacteria, fungi.

          ( vi ) Producers.

          ( vii ) Unidirectional.

          ( viii ) Light, chemical.

          ( ix ) Producer.

          ( x ) producers.

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