OUR ENVIRONMENT – 2020 Important Question


Q1. State one problem caused by non-biodegradable wastes. 

Q2.  Which of the following materials are non-biodegradable in each of the following category?

(i)  Paper, leather, nylon, eggshell, glass

(ii)   Tea leaves, glass, glucose, cotton cloth, silver foil

(iii)   Glass, glucose, leather,  silver foil, nylon cloth

Q3. State one difference between autotrophs and heterotrophs.

Q4.  Draw a food chain most likely to be a part of a forest ecosystem.

Q5.  Rearrange the following according to their ascending trophic levels in a food chain. Hawk, grass, snake, frog, grasshopper.

Q6. If a harmful chemical enters a food chain comprising fishes,  phytoplankton and birds,  which of the organisms is likely to have minimum concentration of the harmful chemical in its body?

Q7. Rearrange the following according to their trophic levels in a food, chain.

Fish, zooplankton, sea, phytoplankton

Q8.  Which one of the following is always at the third trophic level in a food chain?

Carnivores, herbivores, producers, decomposers.

Q9. In a  food chain  .comprising  lion,  grass and deer, which will

(i)  transfer the maximum amount of energy.

(ii)  receive a minimum amount of energy.

Q10. In the following food chain,   20 J   of energy was available to the hawks. How much would have been present in the plants?         –

Plants → rats → snakes → hawks

Q11. If a   harmful chemical enters in food chain comprising snakes,  peacock,  mice and plants, which of these organisms is likely to have the maximum concentration of this chemical in its body?

Q12. The level of energy reaching from one to next higher trophic level decreases. Suggest a reason for this occurrence.

Q13. If the ozone layer disappears completely, what will be the consequences?

Q14. Name the group of chemical compounds which adversely affects the ozone layer?

Q15. To keep the environment clean, garbage disposal programme is an essential prerequisite. What methods constitute the garbage disposal programme?

Q16. List two methods of safe disposal of the non-biodegradable waste.  

Q17. List two items which can be easily recycled,  but we generally throw them in the dustbins?

Q18. A lake has been polluted by sewage. On comparison with the sample of unpolluted water, the water in the lake is found to have increased contents of some components. Identify these components.

Q19. Why should biodegradable and non-biodegradable wastes be discarded in two separate dustbins?  

Q20.  Write one negative effect of the affluent lifestyle of few persons of a society on the environment.

Q21. List two man-made ecosystems.

Q22. Name the two abiotic components of ecosystem.

Q23. The first trophic level in a food chain is always a green plant. Why?

Q24. Pesticides added to a field is seen in increased amount in the crop and in the birds that feed on them. What is this phenomenon called?

Q25. Why are some substance non-biodegradable?

Q26. Mention one negative effect of our affluent lifestyle on the environment.

Q27. State a way to prevent the accumulation of harmful chemicals in our bodies.

Q28.  What is the ultimate source of energy in an ecosystem?

Q29. What happens when high energy ultraviolet radiations act on the oxygen at a higher level of atmosphere?

Q30.       Are plants actually producers of energy?

Q31.       How is being a vegetarian advantageous in terms of energy?

Q32.       Does change in lifestyle add waste to the environment?

Q33.       Give the difference between paper and glass as a waste product.

Direction (Q. Nos. 34 – 38) In each of the following questions, a statement of Assertion is given by the corresponding statement of Reason. Of the statements, mark the correct answer as

(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion              ·

(b) If both Assertion and Reason are true, but Reason is not the correct explanation of Assertion

(c) If Assertion is true, but Reason is false

(d) If Assertion is false, but Reason is true

(e) If Assertion and Reason both are false

Q34. Assertion: Food chains generally consists of more than four trophic levels.

            Reason: There is loss of energy at each trophic level and very little usable energy remains after four trophic levels.

Q35. Assertion: Certain pesticides and other chemicals used to protect our crops from diseases and pests are non-bio degradable.

            Reason: They do not get accumulated at various trophic levels.

Q36. Assertion: Ozone Layer protects life on earth by blocking out Infrared rays of the Sun.

            Reason: Infra-red rays cause cancer in human beings.

Q37. Assertion: Producers are the largest in number in any food chain.

            Reason: These large number of producers convert the sunlight into energy.

Q38. Assertion: An ecosystem consists of 3 to 4 tropic levels.

            Reason: Removal of Primary consumers will not affect the ecosystem adversely.

Q39.  Which trophic level is occupied by plants in a food chain?

(a) First

(b) Second

(c) Third              

(d) Fourth

Q40.  Which of the following in an example of a human-made ecosystem?

(a) Forest            

(b) Pond

(c) Garden           

(d) Lake

 Q41.  What is the average value for the amount of organic matter that is present at each level of trophic chain and reaches the next level of consumers?

(a) 11%

(b) 10%

(c) 100%             

(d) 50%

Q42. Which. of the following groups of organisms belong to category of producers?

(a) All green plants, fungi and bacteria

(b) All green plants and certain blue-green algae

(c) Bacteria, fungi and blue-green algae

(d) Certain blue-green algae and fungi


Q1. Microorganisms are often referred to as the  ‘scavengers of the environment.’ Elaborate.

Q2. Give three differences between food chain and food web.

Q3.  We often observe domestic waste decomposing in the bylanes of residential colonies. Suggest, ways to make people realise that the improper disposal of waste is harmful to the environment.   

Q4.         (i)   Ultraviolet radiation from sunlight causes a reaction involving  O2   as reactant. What does that produce?

                 (ii)  What does release of phosphates and nitrates in waterbodies lead to?

Q5. Why is Government of India imposing a ban on the use of polythene bags? Suggest two alternatives to these bags and explain plainly how this ban is likely to improve the environment.

Q6. State  10% law.  Explain with an example of how energy flows through different trophic levels.               

Q7.  ‘Vegetarian food habits can sustain a larger number of people’.   Justify the statement in terms of food chain.

Q8. What is garbage?  What does garbage consist of? What is disposal of waste?

Q9. What will happen if we kill all the organisms in one trophic level?

Q10. Give three examples for reducing the problem of waste disposal? Give any two methods.

Q11. You have been selected to talk on  ‘ozone layer and its protection’  in the school assembly on ‘Environment Day’.

(a) Why should ozone layer be protected to save the environment?

(b) List any two ways that you would stress in your talk to bring in awareness amongst your fellow friends that would also help in protection of the ozone layer as well as the environment.

Q12. Write the major cause of ozone depletion. What steps should be taken to limit the damage to ozone layer?

Q13. Suggest one word for each of the following statements/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.

Q14. How does study of food chain in an area or habitat help us? Give an example of four-step food chain operating in a large lake.


Q1. Suggest any five activities in daily life, which are eco-friendly.      

Q2. Name the wastes which are generated in your house daily. What measures would take for their disposal. 

Q3. (a) What is ‘environmental pollution’?

         (b) Distinguish between biodegradable and non-biodegradable pollutants.  ·

         (c) Choose the non-biodegradable pollutants from the list given below

Paper, DDT, Radioactive waste, Plastic, Insecticides.

Q4. (a) What are consumers? What will be the consequence of the absence of primary consumers in an ecosystem?

         (b) What will be the direction of energy transfer in each of the following cases?

(i) Grasshopper eaten by a frog

(ii) Deer feeds on grass

(iii) Deer eaten by a Lion

Q5.   What is environment? What type of substances are the major pollutants of the environment?

Q6.   An industry is being established near a town. How can the wastes generated from this industry affect the local environment?

Q7.   Categorise some of the activities performed by you as an eco-friendly person. Suggest some more eco-friendly activities which we should adopt in day-to-day life.


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