CBSE Class 9 Science Improvement in food resources Sure Shot Questions Set 03

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ASSIGNMENT QUESTIONS SET - 3

CHAPTER - 15

IMPROVEMENT IN FOOD RESOURCES

1. Which one is an oil yielding plant among the following? [1 Mark]
(a) Lentil
(b) Sunflower
(c) Cauliflower
(d) Hibiscus

Answer: (b) Sunflower

1. Sunflower seeds are rich in fats and oils.
2. Lentils provide proteins, while cauliflower is a vegetable.
3. Hence, the correct option is (b).

Teacher's Note:
a) Oil-yielding crops provide essential fatty acids.
b) Sunflower is a major oilseed crop.

2. Which one is not a source of carbohydrate? [1 Mark]
(a) Rice
(b) Millets
(c) Sorghum
(d) Gram

Answer: (d) Gram

1. Rice, millets, and sorghum are cereal crops rich in carbohydrates.
2. Gram is a pulse, which is primarily a source of proteins.
3. Hence, the correct option is (d).

Teacher's Note:
a) Cereals provide carbohydrates for energy.
b) Pulses like gram supply proteins for body building.

3. Find out the wrong statement from the following [1 Mark]
(a) White revolution is meant for increase in milk production
(b) Blue revolution is meant for increase in fish production
(c) Increasing food production without compromising with environmental quality is called as sustainable agriculture
(d) None of the above

Answer: (d) None of the above

1. White revolution relates to milk production, making statement (a) correct.
2. Blue revolution relates to fish production, making statement (b) correct.
3. Sustainable agriculture refers to increasing food production without harming the environment, making statement (c) correct.
4. Since all statements are correct, the wrong statement is none of them, so the correct option is (d).

Teacher's Note:
a) Revolution terms denote large-scale production improvements.
b) Read every option carefully when checking correctness.

4. To solve the food problem of the country, which among the following is necessary? [1 Mark]
(a) Increased production and storage of food grains
(b) Easy access of people to the food grain
(c) People should have money to purchase the grains
(d) All of the above

Answer: (d) All of the above

1. Food security requires both availability through production and storage.
2. Food grains must be accessible to citizens, and they must have purchasing power.
3. Therefore, all these factors are necessary, making (d) the correct option.

Teacher's Note:
a) Food security depends on availability, accessibility, and affordability.
b) Production alone cannot solve hunger without proper distribution and purchasing power.

5. Find out the correct sentence [1 Mark]
(i) Hybridisation means crossing between genetically dissimilar plants
(ii) Cross between two varieties is called as inter specific hybridisation
(iii) Introducing genes of desired character into a plant gives genetically modified crop
(iv) Cross between plants of two species is called as inter varietal hybridisation
(a) (i) and (iii)
(b) (ii) and (iv)
(c) (ii) and (iii)
(d) (iii) and (iv)

Answer: (a) (i) and (iii)

1. Statement (i) is correct because hybridisation involves crossing genetically dissimilar plants.
2. Statement (iii) is correct as introducing desired genes creates genetically modified crops.
3. Statement (ii) is incorrect because a cross between two varieties is inter-varietal, not inter-specific.
4. Statement (iv) is incorrect because a cross between two species is inter-specific, not inter-varietal, so option (a) is correct.

Teacher's Note:
a) Inter-varietal means between different varieties.
b) Inter-specific means between different species.

6. Weeds affect the crop plants by [1 Mark]

Answer:
1. Competing with crop plants for nutrients, space, sunlight, and water.
2. Reducing overall crop yield and quality.

Teacher's Note:
a) Weeds are unwanted plants in cultivated fields.
b) Early weed removal is essential for healthy crop growth.

6. Weeds affect the crop plants by: [1 Mark]
(a) killing of plants in field before they grow
(b) dominating the plants to grow
(c) competing for various resources of crops (plants) causing low availability of nutrients
(d) all of the above.

Answer: (c) competing for various resources of crops (plants) causing low availability of nutrients

1. Weeds are unwanted plants in the cultivated field.
2. They compete with crop plants for light, water, space and nutrients.
3. This competition reduces the availability of essential resources for the main crops.
4. Hence, the correct option is (c).

Teacher's Note:
a) Weeds deprive crops of essential nutrients.
b) They lower overall crop yield significantly.

7. Which one of the following species of honey bee is an Italian species? [1 Mark]
(a) Apis dorsata
(b) Apis florae
(c) Apis cerana indica
(d) Apis mellifera

Answer: (d) Apis mellifera

1. Apis mellifera is commonly known as the Italian bee variety.
2. It is frequently used for commercial honey production due to its high honey collection capacity.
3. It stings less and stays in a given beehive for longer periods.
4. Hence, the correct option is (d).

Teacher's Note:
a) Apis cerana indica is the Indian bee.
b) Apis dorsata is the rock bee.

8. Find out the correct sentence about manure [1 Mark]
(i) Manure contains large quantities of organic matter and small quantities of nutrients.
(ii) It increases the water holding capacity of sandy soil.
(iii) It helps in draining out of excess of water from clayey soil.
(iv) Its excessive use pollutes environment because it is made of animal excretory waste.
(a) (i) and (iii)
(b) (i) and (ii)
(c) (ii) and (iii)
(d) (iii) and (iv)

Answer: (b) (i) and (ii)

1. Statement (i) is correct because manure is prepared from organic waste and supplies small amounts of nutrients.
2. Statement (ii) is correct as organic matter improves water retention in sandy soils.
3. Statement (iii) describes a benefit of manure in clayey soil (better drainage), but among the given options the best pairing is (i) and (ii). Also statement (iv) is false because manure is organic and does not pollute the environment like synthetic fertilizers.
4. Hence, the correct combination is (i) and (ii), making option (b) correct.

Teacher's Note:
a) Manures enrich soil with organic matter.
b) They are eco-friendly and prevent soil pollution.

9. Cattle husbandry is done for the following purposes [1 Mark]
(i) Milk Production
(ii) Agricultural work
(iii) Meat production
(iv) Egg production
(a) (i), (ii) and (iii)
(b) (ii), (iii) and (iv)
(c) (iii) and (iv)
(d) (i) and (iv)

Answer: (a) (i), (ii) and (iii)

1. Cattle are reared for milk production (milch animals).
2. They are used for agricultural work like tilling, irrigation and carting (draught animals).
3. Certain cattle breeds are also used for meat production.
4. Egg production is related to poultry, not cattle husbandry.

Teacher's Note:
a) Cattle husbandry covers both dairy and draught purposes.
b) Poultry farming deals with egg and meat production from birds.

10. Which of the following are Indian cattle? [1 Mark]
(i) Bos indicus
(ii) Bos domestica
(iii) Bos bubalis
(iv) Bos vulgaris
(a) (i) and (iii)
(b) (i) and (ii)
(c) (ii) and (iii)

(d) (ii) and (iv)

Answer: (a) (i) and (iii)

1. Bos indicus is the scientific name for the humped Indian cattle.
2. Bos bubalis refers to the water buffalo, commonly found and raised in India.
3. Bos domestica and Bos vulgaris are not standard valid classifications for Indian cattle here.
4. Hence, statements (i) and (iii) are correct, making option (a) the right choice.

Teacher's Note:
a) Learn scientific names of important farm animals.
b) Bos indicus represents cows and Bos bubalis represents buffaloes.

11. Which of the following are exotic breeds? [1 Mark]
(i) Brawn
(ii) Jersey
(iii) Brown Swiss
(iv) Jersey Swiss
(a) (i) and (iii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) (ii) and (iv)

Answer: (b) (ii) and (iii)

1. Jersey and Brown Swiss are well-known exotic (foreign) breeds of cattle known for their high milk production.
2. Exotic breeds are imported from other countries to crossbreed with local varieties for better yield.
3. Hence, the correct option is (b).

Teacher's Note:
a) Exotic breeds offer longer lactation periods.
b) Indigenous breeds are more disease-resistant.
c) Jersey cattle originate from the island of Jersey in the UK.

12. Poultry farming is undertaken to raise following [1 Mark]
(i) Egg production
(ii) Feather production
(iii) Chicken meat
(iv) Milk production
(a) (i) and (iii)
(b) (i) and (ii)
(c) (ii) and (iii)
(d) (iii) and (iv)

Answer: (a) (i) and (iii)

1. Poultry farming is raised primarily for egg production (layers) and chicken meat (broilers).
2. Milk production is associated with dairy farming, not poultry.
3. Hence, the correct option is (a).

Teacher's Note:
a) Layers produce eggs, while broilers are raised for meat.
b) Proper housing and feed are essential for poultry health.
c) Feathers are a minor byproduct, not the primary purpose of poultry farming.

13. Poultry fowl are susceptible to the following pathogens [1 Mark]
(a) Viruses
(b) Bacteria
(c) Fungi
(d) All of the above

Answer: (d) All of the above

1. Poultry birds can contract diseases caused by viruses, bacteria, and fungi.
2. Common pathogens cause infections like bird flu (viral) or cholera (bacterial).
3. Hence, the correct option is (d).

Teacher's Note:
a) Vaccination helps prevent viral and bacterial outbreaks.
b) Sanitation and hygiene control fungal growth in poultry farms.
c) Parasites can also affect poultry health.

14. Which one of the following fishes is a surface feeder? [1 Mark]
(a) Rohus
(b) Mrigals
(c) Common carps
(d) Catlas

Answer: (d) Catlas

1. Catlas are surface feeders that feed on plankton in the upper layers of water.
2. Rohus feed in the middle zone (column feeders), while Mrigals and Common carps are bottom feeders.
3. Hence, the correct option is (d).

Teacher's Note:
a) Composite fish culture uses different feeding zones to avoid food competition.
b) Catla, Rohu, and Mrigal are stocked together in ponds.
c) Surface, middle, and bottom feeders utilize all available food efficiently.

15. Animal husbandry is the scientific management of [1 Mark]
(i) animal breeding
(ii) culture of animals
(iii) animal livestock
(iv) rearing of animals
(a) (i), (ii) and (iii)

(b) (ii), (iii) and (iv)
(c) (i), (ii) and (iv)
(d) (i), (iii) and (iv)

Answer: (a) (i), (ii) and (iii)

1. Animal husbandry deals with feeding, breeding, and disease control of livestock.
2. It encompasses the scientific management of animal livestock, breeding, and culture.
3. Hence, the correct option is (a).

Teacher's Note:
a) Animal husbandry meets the growing demand for milk, eggs, and meat.
b) Proper breeding improves desirable traits in livestock.
c) Proper shelter and veterinary care are core components.

16. Which one of the following nutrients is not available in fertilizers? [1 Mark]
(a) Nitrogen
(b) Phosphorus
(c) Iron
(d) Potassium

Answer: (c) Iron

1. Fertilizers mainly supply macronutrients such as nitrogen, phosphorus, and potassium.
2. Iron is a micronutrient required in very small quantities and is typically supplied by soil minerals rather than commercial fertilizers.
3. Hence, the correct option is (c).

Teacher's Note:
a) Fertilizers supply major plant nutrients.
b) Iron is classified as a trace element.

17. Preventive and control measures adopted for the storage of grains include [1 Mark]
(a) strict cleaning
(b) proper disjoining
(c) fumigation
(d) all of the above

Answer: (d) all of the above

1. Strict cleaning ensures grains are free from debris and moisture before storage.
2. Fumigation uses chemicals to kill pests in closed storage spaces.
3. Hence, all listed preventive measures are correct, making option (d) the right choice.

Teacher's Note:
a) Grain storage requires multi-step protection.
b) Both physical and chemical methods are used.

18. Match the column A with the column B [1 Mark]

Answer: (a)-(ii), (b)-(iii), (c)-(i), (d)-(iv)

1. Catla are surface feeders feeding on plankton.
2. Rohu feed in the middle zone of the water body.
3. Mrigal and common carp are bottom feeders.
4. Fish farming is also known as culture fishery.

Teacher's Note:
a) Composite fish culture uses different feeding zones to avoid food competition.
b) Match each fish species correctly.

19. Fill in the blanks [1 Mark]
(a) Pigeon pea is a good source of protein.
(b) Berseem is an important fodder crop.
(c) The crops which are grown in rainy season are called kharif crops.
(d) Fruits and vegetables are rich in vitamins.
(f) Rabi crop grows in winter season.

Answer:
(a) protein
(b) fodder
(c) kharif
(d) Fruits and vegetables (or Vegetables)
(f) Rabi

Teacher's Note:
a) Pulses like pigeon pea provide proteins.
b) Berseem is grown as livestock feed.

20. What is a GM crop? Name any one such crop which is grown in India. [2 Marks]

Answer:
1. Genetically Modified (GM) crops are plants whose DNA has been altered using genetic engineering techniques to introduce desirable traits.
2. Bt cotton is an example of a GM crop grown in India.

Teacher's Note:
a) GM crops help in pest resistance and improved yield.
b) Bt cotton is resistant to bollworms.

21. List out some useful traits in improved crop? [2 Marks]

Answer:
1. Higher yield to increase agricultural productivity per acre.
2. Improved resistance to biotic stresses (diseases, insects) and abiotic stresses (drought, salinity).
3. Desirable agronomic characteristics like dwarfness in cereals or tallness in fodder crops.

Teacher's Note:
a) Crop improvement aims at food security.
b) Traits are bred through hybridization.

22. Why is organic matter important for crop production? [2 Marks]

Answer:
1. Organic matter helps in improving soil texture, water retention capacity, and aeration.
2. It supplies essential nutrients to the soil and promotes the activity of helpful soil microorganisms.

Teacher's Note:
a) Manure adds organic matter to the soil.
b) It corrects soil physical properties.

23. Why is excess use of fertilizers detrimental for environment? [2 Marks]

Answer:
1. Excess fertilizers wash into water bodies, causing eutrophication and depleting dissolved oxygen.
2. They can also alter soil chemistry, reduce soil fertility over time, and pollute groundwater.

Teacher's Note:
a) Chemical fertilizers should be used in judicious amounts.
b) Runoff causes algal blooms in lakes.

24. Give one word for the following [3 Marks]
(a) Farming without the use of chemicals as fertilizers, herbicides and pesticides is known as organic farming.
(b) Growing of wheat and groundnut on the same field is called as mixed cropping.
(c) Planting soyabean and maize in alternate rows in the same field is called as intercropping.

Answer:
(a) Organic farming
(b) Mixed cropping
(c) Intercropping

Teacher's Note:
a) Organic farming maintains environmental health.
b) Intercropping uses specific row patterns to maximize crop yield.

(d) Growing different crops on a piece of land in pre-planned succession is known as - ____. [1 Mark]

Answer:
1. Crop rotation.
2. It helps in maintaining soil fertility and reducing pest incidence.

Teacher's Note:
a) Crop rotation prevents the depletion of specific nutrients from the soil.
b) Different crops have different nutrient requirements.

(e) Xanthium and Parthenium are commonly known as - ____. [1 Mark]

Answer:
1. Weeds.
2. They compete with crops for nutrients, space, and light.

Teacher's Note:
a) Weeds are unwanted plants that grow cultivated fields.
b) Timely weeding is essential for healthy crop growth.

(f) Causal organism of any disease is called as - ____. [1 Mark]

Answer:
1. Pathogen.
2. Pathogens include bacteria, fungi, and viruses.

Teacher's Note:
a) Pathogens disrupt normal physiological functions of the host organism.
b) Identifying the pathogen helps in selecting the correct treatment or pesticide.

25. Match the following A and B [5 Marks]

Teacher's Note:
a) Animal husbandry classifies cattle based on utility into milch and draught animals.
b) Broilers are specifically raised for poultry meat production.
c) Indigenous cattle breeds like Sahiwal possess high resistance to diseases.
d) Correct matching pairs are derived directly from agricultural classification of livestock and poultry.

26. If there is low rainfall in a village throughout the year, what measures will you suggest to the farmers for better cropping? [3 Marks]

Answer:
1. Use drought-resistant and early-maturing crop varieties.
2. Adopt efficient irrigation techniques like drip irrigation and sprinkler systems.
3. Implement water conservation practices such as rainwater harvesting and mulching to retain soil moisture.

Teacher's Note:
a) Water scarcity limits crop yields in arid regions.
b) Drip irrigation minimizes water wastage by delivering moisture directly to plant roots.
c) Mulching prevents evaporation from the soil surface.

27. Group the following and tabulate them as energy yielding, protein yielding, oil yielding and fodder crop: Wheat, rice, berseem, maize, gram, oat, pigeon gram, sudan grass, lentil, soyabean, groundnut, castor and mustard. [4 Marks]

Answer:

Teacher's Note:
a) Cereals like wheat, rice, and maize provide carbohydrates for energy.
b) Legumes like gram, lentil, and pigeon gram are rich sources of proteins.
c) Oilseeds provide essential fats and oils for human consumption.
d) Certain crops like soyabean overlap between protein and oil yielding categories.

28. Define the term hybridization and photoperiod. [2 Marks]

Answer:
1. Hybridization is crossing genetically dissimilar plants to obtain a new variety with desirable characters like high yield and disease resistance.
2. Photoperiod refers to the duration of daily exposure to sunlight, which influences plant growth and flowering.

Teacher's Note:
a) Hybridization can be intervarietal, interspecific, or intergeneric.
b) Photoperiodism is critical for determining seasonal crop adaptability and flowering times.

29. Fill in the blanks [5 Marks]
(a) Photoperiod affect the - - - - .
(b) Kharif crops are cultivated from - - - - to - - - - .
(c) Rabi crops are cultivated from - - - - to - - - - .
(d) Paddy, maize, green gram and black gram are - - - - crops.
(e) Wheat, gram, pea, mustard are - - - - crops.

Answer:
(a) flowering.
(b) June, October.
(c) November, April.
(d) Kharif.
(e) Rabi.

Teacher's Note:
a) Photoperiod is directly linked to the physiological response of flowering in plants.
b) Kharif seasons coincide with the rainy season in India.
c) Rabi seasons correspond to the winter season.
d) Classification of seasonal crops is based on their sowing and harvesting periods.

30. Cultivation practices and crop yield are related to environmental condition. Explain. [3 Marks]

Answer:
1. Weather parameters like temperature, humidity, and rainfall directly control vegetative growth and grain development.
2. Different crops require specific photoperiods and temperature ranges for optimal metabolic activity and flowering.
3. Appropriate cultivation practices like timely irrigation and fertilizer application help mitigate adverse environmental fluctuations to maximize yield.

Teacher's Note:
a) Environmental conditions dictate the choice of crop variety for a specific region.
b) Unseasonal rain or extreme drought can severely damage standing crops.
c) Agricultural technology helps optimize growth parameters despite climatic variations.

31. Fill in the blanks [6 Marks]
(a) A total of - - - nutrients are essential to plants.
(b) - - - and - - - are supplied by air to plants.
(c) - - - is supplied by water to plants.
(d) Soil supply - - - nutrients to plants.
(e) - - - nutrients are required in large quantity and called as - - - .
(f) - - - nutrients are needed in small quantity for plants and are called - - - .

Answer:
(a) 16.
(b) Carbon, oxygen.
(c) Hydrogen.
(d) 13.
(e) Macro, macronutrients.
(f) Micro, micronutrients.

Teacher's Note:
a) Plants obtain carbon and oxygen from carbon dioxide in the air.
b) Hydrogen is obtained from water absorbed by roots.
c) Out of 16 essential elements, 13 are supplied by the soil.
d) Macronutrients and micronutrients are categorized based on quantitative requirements.

32. Differentiate between compost and vermicompost? [2 Marks]

Answer:

Teacher's Note:
a) Both types of manure improve soil structure and water-holding capacity.
b) Vermicomposting utilizes specific earthworm species such as red worms.

33. Arrange these statements in correct sequence of preparation of green manure. [2 Marks]
(a) Green plants are decomposed in soil.
(b) Green plants are cultivated for preparing manure or crop plant parts are used.

Answer:
1. (b) Green plants are cultivated for preparing manure or crop plant parts are used.
2. (a) Green plants are decomposed in soil.

Teacher's Note:
a) Green manure helps enrich the soil in nitrogen and phosphorus.
b) Fast-growing plants are ploughed back into the soil before they flower.

34. An Italian bee variety A. mellifera has been introduced in India for honey production. Write about its merits over other varieties. [3 Marks]

Answer:
1. They have high honey collection capacity.
2. They sting less frequently and are relatively gentle in nature.
3. They stay in the beehive for long periods and breed very well.

Teacher's Note:
a) This exotic variety is widely used in commercial apiculture due to its superior productivity.
b) Students must remember to mention both behavioral and yield-related advantages.
c) The scientific name should be underlined or written correctly with italics if possible.

35. In agricultural practices, higher input gives higher yield. Discuss how? [3 Marks]

Answer:
1. Financial inputs allow farmers to use better quality seeds and high yielding varieties.
2. Increased investment enables better crop nutrition through timely application of manures and fertilizers.
3. Proper financial resources support advanced irrigation and effective pest management, protecting crops and maximizing overall output.

Teacher's Note:
a) Financial input is directly proportional to the level of technology and care a crop receives.
b) Avoid writing only about fertilizers; encompass seeds, irrigation, and protection measures.
c) Connect economic investment with biological productivity in agricultural systems.

36. Discuss the role of hybridisation in crop improvement. [3 Marks]

Answer:
1. Hybridisation refers to crossing genetically dissimilar plants to combine desirable characters.
2. It helps in developing high yielding varieties with improved resistance to biotic and abiotic stresses.
3. It improves crop quality, maturity duration, and adaptability to diverse climatic conditions.

Teacher's Note:
a) Cross-breeding between different varieties creates new combinations of traits.
b) Make sure to specify both biotic stresses (diseases, insects) and abiotic stresses (drought, salinity).
c) Hybrid vigour or heterosis is a key concept associated with successful hybridisation programmes.

37. Define (i) Vermicompost
(ii) Green manure
(iii) Bio fertilizer [3 Marks]

Answer:
(i) Vermicompost: The process of producing compost using earthworms that breakdown organic matter.
(ii) Green manure: Fast growing green plants ploughed back into the soil to enrich it with nitrogen and phosphorus.
(iii) Bio fertilizer: Living organisms like bacteria, algae, and fungi that enrich the soil nutrient quality.

Teacher's Note:
a) Each term represents a sustainable method of soil enrichment without chemical overload.
b) Do not confuse green manure with farmyard manure.
c) Bio fertilizers primarily utilize nitrogen-fixing microbes and phosphate-solubilizing agents.

38. Discuss various methods for weed control. [3 Marks]

Answer:
1. Mechanical removal includes weeding by uprooting, hand pulling, or using implements like trowels.
2. Preventive methods involve proper seed bed preparation, timely sowing, and crop rotation.
3. Chemical control utilizes specific weedicides or herbicides to destroy unwanted plants without harming the main crop.

Teacher's Note:
a) Weeds compete with crops for light, water, and nutrients.
b) Emphasize biological control methods as an eco-friendly alternative where specific insects eat weeds.
c) Overuse of chemical weedicides can cause environmental pollution and health hazards.

39. Differentiate between the following
(i) Capture fishery and Culture fishery
(ii) Mixed cropping and Inter cropping
(iii) Bee keeping and Poultry farming [3 Marks]

Answer:

Teacher's Note:
a) Differentiate questions are best answered in a clear tabular format.
b) Ensure clear distinction in row patterns for cropping and natural versus artificial sources for fisheries.
c) Accuracy in definitions secures full credit.

40. Give the merits and demerits of fish culture? [2 Marks]

Answer:
1. Merits: High yield of desired fish species can be obtained in a small area, and it ensures a continuous supply of fish.
2. Demerits: It requires high initial investment, and disease outbreak can spread rapidly among densely stocked fish populations.

Teacher's Note:
a) Fish culture allows composite fish culture where compatible species utilize different zones of a pond.
b) Mention both economic advantages and biological risks like disease susceptibility.

41. Below Figure shows the two crop fields [Plots A and B] have been treated by manures and chemical fertilizers respectively, keeping other environmental factors same. Observe the graph and answer the following questions.
(i) Why does plot B show sudden increase and then gradual decrease in yield?
(ii) Why is the highest peak in plot A graph slightly delayed?
(iii) What is the reason for the different pattern of the two graphs? [3 Marks]

[Figure: Line graph with Quantity of amendment on X-axis and % Yield of the crop on Y-axis. Plot A shows a gradual rise and steady peak labeled Manures. Plot B shows a sharp steep rise followed by a drop labeled Chemical fertilizers]

Answer:
(i) Plot B shows a sudden increase due to the immediate release of nutrients by chemical fertilizers, and a decrease due to toxicity caused by excessive fertilizers and soil damage over time.
(ii) The peak in plot A is slightly delayed because manures release nutrients slowly through decomposition by soil microorganisms.
(iii) The different patterns occur because chemical fertilizers act rapidly and can harm soil structure if overused, whereas manures improve soil texture and release nutrients gradually.

Teacher's Note:
a) Chemical fertilizers provide quick nutrition but deplete humus, whereas manures maintain long term soil health.
b) Carefully analyze axis labels before interpreting graph trends.
c) Connect the slow decomposition rate of organic matter with the delayed peak in Plot A.

42. What do you understand by composite fish culture? [2 Marks]

Answer:
1. Composite fish culture is a system where five to six different species of fish are cultured together in a single fish pond.
2. Species are selected so that they do not compete for food, as they have different food habits and occupy different zones of the pond, maximizing total yield.

Teacher's Note:
a) Surface feeders, column feeders, and bottom feeders are combined to use all available food in the pond.
b) Mention examples like Catla, Rohu, and Mrigal for a complete answer.

43. Why bee keeping should be done in good pasturage? [2 Marks]

Answer:
1. Pasturage provides the flowers available to the bees for nectar and pollen collection.
2. Good pasturage with adequate floral resources ensures better quality and quantity of honey produced.

Teacher's Note:
a) Pasturage determines the taste and commercial value of honey.
b) Availability of adequate flora is essential for the survival and nourishment of the bee colony.

44. Write the modes by which insects affect the crop yield. [3 Marks]

Answer:
1. Chewing insects cut plant parts like root, stem, and leaves, destroying foliage and reducing photosynthetic area.
2. Sucking insects suck cell sap from various parts of the plant, weakening the plant and causing stunted growth.
3. Internal borers bore into stems and fruits, damaging internal tissues and rendering the crop unmarketable.

Teacher's Note:
a) Insect pests attack crops at different stages of growth.
b) Categorizing pests by their feeding habit makes the answer comprehensive.
c) Some insect pests also act as vectors for viral and fungal plant diseases.

45. Discuss why pesticides are used in very accurate concentration and in very appropriate manner? [3 Marks]

Answer:
1. Using them in accurate concentrations ensures effective pest eradication without wasting chemicals.
2. Excessive use can lead to soil and water pollution, accumulation of toxic residues in food chains, and harm to beneficial organisms.
3. Precise application prevents pests from developing resistance and protects the health of farmers and consumers.

Teacher's Note:
a) Pesticides are toxic chemicals designed to kill pests but pose environmental risks if mismanaged.
b) Highlight bioaccumulation and biomagnification as consequences of improper pesticide use.
c) Emphasize precision in modern agriculture for sustainable crop protection.

46. Name two types of animal feed and write their functions. [3 Marks]

Answer:
1. Roughage and concentrate are the two types of animal feed.
2. Roughage contains large amount of fibre and provides mostly inert matter necessary for proper digestion.
3. Concentrates are nutrient-rich, low in fibre, and provide necessary proteins and other nutrients for growth and milk production.

Teacher's Note:
a) Animal feed quality directly impacts livestock health and yield.
b) Ensure both components are balanced in the daily ration.
c) Concentrates contain vital macro and micronutrients.

47. What would happen if poultry birds are larger in size and have no summer adaptation capacity? In order to get small sized poultry birds, having summer adaptability, what method will be employed? [3 Marks]

Answer:
1. Larger birds with no summer adaptation require more maintenance energy, suffer from heat stress, and have reduced egg or meat production.
2. Cross-breeding between indigenous and exotic breeds is employed to get desired traits.
3. This hybridisation helps develop small-sized poultry birds with high thermal tolerance and summer adaptability.

Teacher's Note:
a) Cross-breeding combines superior traits of both parent breeds.
b) Smaller body size reduces maintenance feed requirements.
c) Thermal tolerance ensures survival and productivity in hot climates.

48. Suggest some preventive measures for the diseases of poultry birds. [3 Marks]

Answer:
1. Proper cleaning, sanitation, and disinfection of the poultry shelters at regular intervals.
2. Timely vaccination of birds against major viral and bacterial diseases.
3. Maintaining hygienic feeding and drinking water conditions along with isolating infected birds.

Teacher's Note:
a) Prevention is more cost-effective than treatment in poultry farming.
b) Vaccination schedules must be strictly followed.
c) Good ventilation prevents respiratory infections in the flock.

49. Complete the crossword puzzle: [5 Marks]

[Figure: Crossword grid with numbered cells corresponding to across and downward clues for agricultural and animal husbandry terms]

Across
1. Oil yielding plant (9)
3. Crop grown in winter season (4)
5. Fixed by Rhizobium (8)
9. Common honey bee (4)

Downward
2. Animal feed (6)
4. A micronutrient (5)
6. Unwanted plant in crop fields (4)
7. An exotic breed of chicken (7)
8. Bottom feeders in fish pond (7)
10. A marine fish (4)

Answer:
1. Across: 1. Sunflower, 3. Rabi, 5. Nitrogen, 9. Apis
2. Downward: 2. Fodder, 4. Boron, 6. Weed, 7. Leghorn, 8. Mrigals, 10. Tuna
3. Crossword completion requires checking letter counts for each clue.
4. Each word correctly intersects at the numbered grid squares.
5. All terms relate directly to crop production and animal husbandry.

Teacher's Note:
a) Crossword puzzles reinforce scientific terminology in a fun way.
b) Pay close attention to the letter count specified in brackets.
c) Verify intersections like shared vowels to ensure accuracy.
d) Review all agricultural terms regularly for exam preparation.

50. Complete the crossword puzzle : [3 Marks]
Across
1. It is prepared from rotten vegetable matter and animal refuse.
2. A major source of nutrients in fields and an organic substance.
3. The cereal grains are dried before___.
Downward
4. Removal of the grains from the chaff.
5. The process of putting the seeds in the soil.
6. The winter season crops like wheat, barley, gram, pea. etc are called.

[Figure: Crossword grid with numbered clues across and downward: Across - 1. COMPOST, 2. MANURE, 3. STORAGE; Downward - 4. THRESHING, 5. SOWING, 6. RABI]

Answer:
1. Across 1: COMPOST
2. Across 2: MANURE
3. Across 3: STORAGE
4. Downward 4: THRESHING
5. Downward 5: SOWING
6. Downward 6: RABI

Teacher's Note:
a) Crossword puzzles test agricultural terminology and definitions covered in crop production and management.
b) Ensure correct spelling of agricultural terms such as composting, threshing, and rabi crops to avoid losing marks.
c) Read both across and downward clues carefully, keeping letter counts in mind to solve intersecting words.