Solution β harmful effects of agricultural practices on the environment are β Loss of the fertility of the soil by cropping which can also cause soil erosion .Decrease in the underground water level...
37. What are the by-products of fertiliser industries? How do they affect the environment?
Solution β oxides of sulphur and nitrogen are the by β products of the fertiliser industry . Other products include solid , liquid chemicals and some solid waste materials . These results in massive...
36. Suggest suitable mechanism (s) for waste management in fertilizer industries.
Solution β the main waste of the fertilizer industry are the effluents and the harmful gases .To manage the waste emitted by the fertiliser industries following measures can be opted : Some...
35. Name the wastes which are generated in your house daily. What measures would you take for their disposal?
Solution β waste generated in the house and methods used for their disposal are β Waste materialMethod of disposalMilk pouches , poly bagsSafe disposal of plastic bagsDirt and sweeping wasteShould...
34. Give two differences between food chain and food web.
Solution Food chain Food webit is a natural system through which energy is transferred from one organism to the other . It comprises of numerous inter connected food chains . Instability of the...
33. Suggest any four activities in daily life which are eco-friendly .
Solution β the four activities which are eco β friendly in our daily life are β Harvesting of rain water Walking for short distances Using of public transport or encouraging sharing in place of use...
32. What are decomposers? What will be the consequence of their absence in an ecosystem?
Solution β micro β organisms which break down the dead and decaying waste products are known as the decomposers . They break down the complex organic substances into simpler ones . These substances...
31. Indicate the flow of energy in an ecosystem. Why is it unidirectional? Justify.
Solution β the flow of energy via living things in an ecosystem is known as the energy flow . All living organisms are categorized into producers and consumers . Further these producers and...
30. We do not clean ponds or lakes, but an aquarium needs to be cleaned. Why
Solution β pond or a lake is a natural ecosystem so its complete and does not require and cleaning from outside . While an aquariumΒ is an artificial incomplete ecosystem , which needs regular...
29. Select the mismatched pair in the following and correct it.
(a) Biomagnification β Accumulation of chemicals at the successive trophic levels of a food chain (b) Ecosystem β Biotic components of environment (c) Aquarium β A man-made ecosystem (d) Parasites β...
28. Explain the role of decomposers in the environment?
Solution β dead and decaying living matter is broken down by the decomposers present in the environment . They recycle dead animals into chemical nutrients . This aids to maintain the flow of the...
27. Suggest one word for each of the following statements/ definitions
(a) The physical and biological world where we live in (b) Each level of the food chain where the transfer of energy takes place (c) The physical factors like temperature, rainfall, wind and soil of...
26. Differentiate between biodegradable and non-biodegradable substances. Cite examples.
Solution - Biodegradable substancesNon-biodegradable substancesIt refers to any substance that is capable of undergoing biodegradationBy non biodegradable we mean any substance or material that...
25. Why are crop fields known as artificial ecosystems?
Solution β crop fields are artificial ecosystem as the plants in these fields are grown by the man . They are grown in confirmation to the weather , type of soil , land and market requirement . They...
24. What are the advantages of cloth bags over plastic bags during shopping?
Solution - the advantages of cloth bags over plastic bags during shopping are : They can be re β usedThey are bio degradableThey are cost effective as can be used many timesEnvironmental friendlyNo...
23. Write the common food chain of a pond ecosystem.
Solution β a food chain begins with a producer .The most common food chain of a pond ecosystem is as follows : Phyto planktons β Small aquatic animals ( like larvae, shrimps, Insects etc. ) β Fish β...
22. Why is improper disposal of waste a curse to the environment?
Solution β improper disposal of waste is a curse to environment . It is so because it pollutes our environment ( which includes air , water and soil ) . This results in harmful effects on the human...
21. Disposable plastic plates should not be used because
(a) they are made of materials with lightweight (b) they are made of toxic materials (c) they are made of biodegradable materials (d) they are made of non-biodegradable materials Correct option β (...
20. If a grasshopper is eaten by a frog, then the energy transfer will be from
(a) producer to decomposer (b) producer to primary consumer (c) primary consumer to secondary consumer (d) secondary consumer to primary consumer Correct option β ( c ) Explanation for correct...
19. The decomposers in an ecosystem
(a) convert inorganic material, to simpler forms (b) convert organic material to inorganic forms (c) convert inorganic materials into organic compounds (d) do not breakdown organic compounds Correct...
18. What will happen if deer is missing in the food chain given below? Grass β Deer β Tiger
(a) The population of tiger increases (b) The population of grass decreases (c) Tiger will start eating grass (d) The population of tiger decreases and the population of grass increases Correct...
17. In the given Figure 15.1 the various trophic levels are shown in a pyramid. At which trophic level is maximum energy available?
(a) T4 (b) T2 (c) T1 (d) T3 Correct option β ( T1 ) Explanation for correct option β the maximum energy will be available at the trophic level T1 . For producers maximum amount of energy is...
16. The percentage of solar radiation absorbed by all the green plants for the process of photosynthesis is about
(a) 1 % (b) 5 % (c) 8 % (d) 10 % Correct option β ( a ) Explanation for correct option β plants prepare there food in the presence of sunlight and chlorophyll and water . Photosynthetically active...
15. Which group of organisms are not constituents of a food chain?
(i) Grass, lion, rabbit, wolf (ii) Plankton, man, fish, grasshopper (iii) Wolf, grass, snake, tiger (iv) Frog, snake, eagle, grass, grasshopper (a) (i) and (iii) (b) (iii) and (iv) (c) (ii) and...
14. Which of the statement is incorrect?
(a) All green plants and blue-green algae are producers (b) Green plants get their food from organic compounds (c) Producers prepare their own food from inorganic compounds (d) Plants convert solar...
13. Which of the following limits the number of trophic levels in a food chain?
(a) Decrease in energy at higher trophic levels (b) Sufficient food supply (c) Polluted air (d) Water Correct option β( a ) Explanation for correct answer β at a particular trophic level the...
12. In the following groups of materials, which group (s) contains only non-biodegradable items?
(i) Wood, paper, leather (ii) Polythene, detergent, PVC (iii) Plastic, detergent, grass (iv) Plastic, bakelite, DDT (a) (iii) (b) (iv) (c) (i) and (iii) (d) (ii) and (iv) Correct option β ( d )...