CBSE Class 9 Science Improvement in food resources Sure Shot Questions Set 02

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ASSIGNMENT QUESTIONS SET - 2
CHAPTER - 15
IMPROVEMENT IN FOOD RESOURCES

1. State one demerit with composite fish culture system. [1 Mark]

Answer:
1. A major demerit of composite fish culture is that many of these fish feed only on food available at specific parts of the reservoir.
2. For example, catlas are surface feeders, rohus feed in the middle-zone, and mrigals and common carps are bottom feeders.
3. However, a significant problem is that many fish compete for the same food source, and some species breed only in rivers, making the availability of good quality seed a major limitation.

Teacher's Note:
a) Composite fish culture uses five or six species in a single pond to utilize all available food zones.
b) The primary challenge is obtaining pure fish seed mixed with other species.
c) Mentioning the competition for food or lack of seed availability is sufficient to earn full credit.

2. State one importance of photoperiod in agriculture. [1 Mark]

Answer:
1. Photoperiod refers to the duration of sunlight received by plants daily.
2. It is crucial because plant growth, flowering, and maturity depend directly on the duration of sunlight.
3. Photosynthesis rates and overall crop yield are heavily influenced by these light variations.

Teacher's Note:
a) Photoperiod is tied to day length and seasonal changes.
b) Emphasize its direct role in plant flowering and vegetative growth to avoid incomplete definitions.

3. Name one micronutrient and one macronutrient which plants take from the soil. [1 Mark]

Answer:
1. Micronutrient taken from the soil: Iron (Fe) or Zinc (Zn).
2. Macronutrient taken from the soil: Nitrogen (N) or Phosphorus (P).

Teacher's Note:
a) Micronutrients are required by plants in small quantities, while macronutrients are required in larger amounts.
b) Students must name one of each correctly to secure full marks.

4. List two desirable traits for fodder crops. [1 Mark]

Answer:
1. Desirable trait 1: High nutritional value and palatable to livestock.
2. Desirable trait 2: Profuse branching and tallness so that it yields abundant biomass.

Teacher's Note:
a) Fodder crops like berseem, oats, or sudan grass are raised as food for livestock.
b) Focus on high yield and high nutritive value as key traits desired by farmers.

5. Distinguish between a mullet and a prawn. [1 Mark]

Answer:
1. A mullet is a finfish possessing a true vertebral column, scales, and fins.
2. A prawn is a crustacean belonging to the invertebrate group with an exoskeleton and jointed appendages.

Teacher's Note:
a) Mullets are true marine or estuarine finfish.
b) Prawns are shell-bearing aquatic invertebrates belonging to crustaceans.

6. Name two breeds of cows selected for long lactation period. [1 Mark]

Answer:
1. Exotic or cross-bred cows are typically selected for extended lactation periods.
2. Examples include Jersey and Brown Swiss.

Teacher's Note:
a) Lactation period refers to the duration of milk production after giving birth.
b) Cross-bred varieties combine the disease resistance of local breeds with the high milk yield and long lactation period of exotic breeds.

7. How does Bombay duck differ from common carp ? [1 Mark]

Answer:
1. Bombay duck is a marine water fish found in coastal areas and marine environments.
2. Common carp is a freshwater fish cultured mainly in freshwater ponds, lakes, and rivers.

Teacher's Note:
a) Habitat is the main distinguishing factor between marine and freshwater fishes.
b) Bombay duck (Harpadon nehereus) is harvested from marine fisheries, while common carp is a freshwater aquaculture species.

8. How does catla differ from mrigal? [1 Mark]

Answer:
1. Catla is a surface feeder fish that consumes food from the upper layer of the water body.
2. Mrigal is a bottom feeder fish that feeds on decaying organic matter and food found at the bottom of the pond.

Teacher's Note:
a) Both are freshwater fish used together in composite fish culture.
b) Their distinct feeding habits prevent food competition in the same pond.

9. Name the two vitamins which are added in the poultry feed. [1 Mark]

Answer:
1. Vitamin A and Vitamin B-complex (or Vitamin C and K) are added to poultry feed.
2. These vitamins are essential for maintaining good health, egg shell quality, and disease resistance in poultry birds.

Teacher's Note:
a) Poultry feed is rich in proteins, carbohydrates, fats, minerals, and vitamins.
b) Vitamins A and K are crucial supplements to prevent deficiencies in layers and broilers.

10. From where do plants acquire the following nutrients? [1 Mark]
(a) Nitrogen
(b) Hydrogen

Answer:
1. (a) Nitrogen: Acquired from the soil, where it is absorbed in the form of inorganic nitrates or nitrites.
2. (b) Hydrogen: Acquired from water (\(\text{H}_2\text{O}\)) taken up from the soil by plant roots.

Teacher's Note:
a) Plants derive nutrients from air, water, and soil.
b) Carbon and oxygen come from air, hydrogen from water, and the remaining 13 nutrients from soil.

11. State the reason of introducing Italian bee variety in bee farms. [1 Mark]

Answer:
1. The Italian bee variety (*Apis mellifera*) is introduced because of its high honey collection capacity.
2. They sting less, stay in a given beehive for longer periods, and breed very well.

Teacher's Note:
a) Commercial honey production relies heavily on this exotic species.
b) Emphasize high honey yield and docile nature as the prime reasons for selection.

12. Mention any two activities for the improvement of crop yield. [1 Mark]

Answer:
1. Crop variety improvement through hybridization and genetic modification.
2. Crop production management involving nutrient management, irrigation, and cropping patterns.

Teacher's Note:
a) Agricultural practices are broadly grouped into crop variety improvement, crop production management, and crop protection management.
b) Mentioning any two distinct scientific practices is required for full credit.

13. Which nutrients are supplied by cereals and pulses ? [1 Mark]

Answer:
1. Cereals provide carbohydrates, which supply energy.
2. Pulses provide proteins, which are essential for body building and tissue repair.

Teacher's Note:
a) Cereals include wheat, rice, maize, and sorghum.
b) Pulses include gram, pea, black gram, and lentil.

14. Name two fresh initiatives taken to increase the water availability for agriculture. [1 Mark]

Answer:
1. Rainwater harvesting.
2. Watershed management (including building check-dams).

Teacher's Note:
a) These initiatives help recharge groundwater tables and prevent soil erosion.
b) Small check-dams stop rainwater from flowing away and reduce run-off.

15. Mention any two advantages of using Italian bee variety in honey production. [1 Mark]

Answer:
1. They sting very little compared to native varieties.
2. They have a significantly higher honey-gathering capacity and breed prolifically.

Teacher's Note:
a) The Italian bee (*Apis mellifera*) is the commercial choice worldwide.
b) Docile behavior and superior honey collection make commercial apiaries profitable.

16. Name any two weeds of crop field. [1 Mark]

Answer:
1. Xanthium (Gokhuru).
2. Parthenium (Congress grass) or Cyperus rotundus (Motha).

Teacher's Note:
a) Weeds are unwanted plants that grow in cultivated fields along with the main crop.
b) They compete with crops for nutrients, space, sunlight, and water.

17. Define animal husbandry. [1 Mark]

Answer:
1. Animal husbandry is the scientific management of animal livestock.
2. It includes various aspects such as feeding, breeding, and disease control of domestic animals.

Teacher's Note:
a) Livestock production includes cattle, goats, sheep, poultry, and fish farming.
b) Proper management ensures better milk, egg, and meat production.

18. What are genetically modified crop? [1 Mark]

Answer:
1. Genetically modified crops are those crops whose DNA has been altered using genetic engineering techniques.
2. This is done to introduce desired traits such as pest resistance, herbicide tolerance, or improved nutritional quality.

Teacher's Note:
a) Also known as GM crops or transgenic crops.
b) Genes conferring desirable agronomic characters are inserted directly into the crop plant's genome.

19. Mention the components of food present in vegetable and fruits. [1 Mark]

Answer:
1. Vitamins and minerals.
2. Dietary fibers, carbohydrates, and water.

Teacher's Note:
a) Fruits and vegetables are protective foods rich in micronutrients.
b) They help prevent deficiency diseases and maintain overall metabolic health.

20. Name the cereals which provide us carbohydrate for energy requirement. [1 Mark]

Answer:
1. Wheat, rice, maize, millet, and sorghum are cereals that provide carbohydrates.

Teacher's Note:
a) Carbohydrates are the primary energy source in human diets.
b) Naming major cereal crops like rice or wheat is sufficient.

21. Give technical term for milk producing females and farm labour animals. [1 Mark]

Answer:
1. Milk-producing female animals are called milch animals (dairy animals).
2. Animals used for farm labor are called draught animals.

Teacher's Note:
a) Milch animals include cows, buffaloes, and goats kept for milk.
b) Draught animals include bullocks, camels, and horses used for agricultural field work and transport.

22. Why do we eat pea and groundnut? [1 Mark]

Answer:
1. We eat peas because they are pulses that provide proteins.
2. We eat groundnuts because they are oilseeds that provide essential fats and fatty acids.

Teacher's Note:
a) Peas are leguminous pulse crops rich in plant protein.
b) Groundnuts are oilseed crops that provide necessary dietary lipids and energy.

23. Name two types of animal feed. [1 Mark]

Answer:
1. Roughage, which is largely fiber-rich feed.
2. Concentrates, which are nutrient-rich and low in fiber.

Teacher's Note:
a) Roughage consists of fodder, silage, and hay.
b) Concentrates include grains, oilcakes, and pulses.

24. Give the full form of FYM. [1 Mark]

Answer:
1. FYM stands for Farmyard Manure.

Teacher's Note:
a) Farmyard manure is prepared using cattle excreta (dung and urine), litter, and leftover organic waste.
b) It enriches the soil with organic matter and essential plant nutrients.

25. Name two main factors responsible for loss during storage of grain. [1 Mark]

Answer:
1. Biotic factors such as insects, rodents, fungi, mites, and bacteria.
2. Abiotic factors such as inappropriate moisture content and temperature of storage.

Teacher's Note:
a) Proper drying and airtight storage prevent heavy grain loss post-harvest.
b) Both living pests and environmental conditions cause severe quantitative and qualitative damage.

26. How much damage to crops can be caused by insects, pests and diseases? [1 Mark]

Answer:
1. Insects, pests, and plant diseases can cause heavy damage, sometimes destroying anywhere from a significant fraction up to total crop loss (or substantial reduction in yield and quality).

Teacher's Note:
a) Pests attack roots, stems, and leaves, sucking cell sap or chewing plant parts.
b) Fungi, bacteria, and viruses cause plant diseases that impair overall crop productivity.

27. Name four macro nutients important for plants. [1 Mark]

Answer:
1. Nitrogen (N), Phosphorus (P), Potassium (K), and Calcium (Ca).

Teacher's Note:
a) Macronutrients are required by plants in large quantities.
b) Other macronutrients include Magnesium, Sulfur, Carbon, Hydrogen, and Oxygen.

28. What is green revolution? [1 Mark]

Answer:
1. Green revolution refers to the dramatic increase in food grain production (especially wheat and rice) achieved through the adoption of high-yielding crop varieties, improved irrigation, fertilizers, and modern agricultural technology.

Teacher's Note:
a) It transformed India from a food-deficient nation into a self-sufficient food producer.
b) Key components included high-yielding varieties (HYV) of seeds.

29. What was the aim of white revolution? [1 Mark]

Answer:
1. The aim of the white revolution (Operation Flood) was to increase milk production and make the country self-sufficient in milk.

Teacher's Note:
a) It is associated with dairy development and cooperative milk marketing.
b) It improved the income of rural farmers through organized milk production and distribution.

30. Name a marine fish. [1 Mark]

Answer:
1. Pomfret is a common marine fish.

Teacher's Note:
a) Marine fish are caught from seas and oceans.
b) Other examples include Tuna, Mackerel, and Sardines.

31. Name the technique of culturing marine fish. [1 Mark]

Answer:
1. Mariculture is the technique of culturing marine fish.

Teacher's Note:
a) It involves rearing marine organisms in enclosed parts of the ocean or specially designed tanks.
b) Fin fishes, prawns, and oysters are commonly cultured using this method.

32. Which vitamins are found high in broilers? [1 Mark]

Answer:
1. Vitamins A and E are found in high amounts in broilers.

Teacher's Note:
a) Broilers are poultry birds specifically bred and fed for meat production.
b) Their daily feed is rich in proteins and vitamins for rapid growth.

33. Which Indian scientist is considered as the father of green revolution? [1 Mark]

Answer:
1. Dr. M. S. Swaminathan is considered as the father of the Green Revolution in India.

Teacher's Note:
a) He played a leading role in introducing high-yielding varieties of wheat and rice in India.
b) His efforts significantly enhanced food grain production in the country.

34. Name a fibres yielding crop. [1 Mark]

Answer:
1. Cotton is a well known fibre yielding crop.

Teacher's Note:
a) Fibre crops are grown for their textile or rope-making fibres.
b) Jute and flax are other examples of fibre yielding crops.

35. Name four types of irrigation systems adopted in our country. [2 Marks]

Answer:
1. Wells (tube wells and dug wells).
2. Canals.
3. Rivers (river lift systems).
4. Tanks.

Teacher's Note:
a) Irrigation is the artificial application of water to land for assisting crop growth.
b) The choice of system depends on water availability and local terrain.

36. Name the members of a honey-bee family. [1 Mark]

Answer:
1. Queen bee, drones, and worker bees.

Teacher's Note:
a) Honey bees live in colonies with a well-defined division of labour.
b) The queen lays eggs, drones fertilise the queen, and workers perform all hive maintenance and foraging.

37. Give two hazards of using fertilizers. [2 Marks]

Answer:
1. Excessive use can destroy soil fertility by damaging soil micro-organisms and organic matter.
2. Run-off from fields can cause water pollution and eutrophication in water bodies.

Teacher's Note:
a) Fertilizers supply plant nutrients but require careful management.
b) Overuse harms both aquatic ecosystems and long-term soil health.

38. Mention two examples of mixed cropping. [1 Mark]

Answer:
1. Wheat and gram.
2. Groundnut and sunflower.

Teacher's Note:
a) Mixed cropping involves growing two or more crops simultaneously on the same piece of land.
b) It minimizes the risk of total crop failure due to pest attack or abnormal weather.

39. Name two factors responsible for losses of grains during storage? [1 Mark]

Answer:
1. Biotic factors such as insects, rodents, fungi, and mites.
2. Abiotic factors such as inappropriate moisture and temperature.

Teacher's Note:
a) Storage losses can be quantitative and qualitative.
b) Proper drying and airtight storage prevent these losses.

40. Name an exotic variety of honey bee grown in India. [1 Mark]

Answer:
1. Apis mellifera (the Italian bee variety).

Teacher's Note:
a) Exotic varieties are introduced to increase honey yield.
b) Apis mellifera has high honey collection capacity and stings less.

41. What is called the rearing of fish on a large scale? [1 Mark]

Answer:
1. Pisciculture (or aquaculture) is the rearing of fish on a large scale.

Teacher's Note:
a) It can be carried out in both fresh water and marine water ecosystems.
b) It is an important source of protein-rich food.

42. List any two methods adopted in farming for the health of the cattle. [2 Marks]

Answer:
1. Providing proper shelter with adequate ventilation and clean flooring.
2. Regular vaccination and timely veterinary check-ups to prevent infectious diseases.

Teacher's Note:
a) Cattle health directly impacts milk production and overall farm economy.
b) Parasite control (both external and internal) is also essential.

43. List the two types of food requirements of dairy animals. [2 Marks]

Answer:
1. Maintenance requirement to support the animal to live a healthy life.
2. Milk-producing requirement during the lactation period.

Teacher's Note:
a) Cattle feed consists of roughage and concentrates.
b) Balanced rations ensure optimal health and milk yield.

44. What are rabi crops? State any two examples. [2 Marks]

Answer:
1. Crops grown during the winter season (from November to April) are called rabi crops.
2. Examples: Wheat and gram.

Teacher's Note:
a) Rabi crops depend on winter rainfall or irrigation.
b) Peas and mustard are other common examples.

45. List two demerits of the continuous use of fertilizers. [2 Marks]

Answer:
1. It reduces soil fertility over time by destroying organic matter and helpful soil microbes.
2. It causes water pollution through agricultural run-off leading to eutrophication.

Teacher's Note:
a) Fertilizers provide short-term high yields.
b) Sustainable practices require combining them with organic manure.

46. List any two advantages of crop rotation. [2 Marks]

Answer:
1. It helps in replenishing soil nutrients naturally, especially when leguminous crops are included.
2. It reduces pests, weeds, and diseases by breaking their life cycles.

Teacher's Note:
a) Crop rotation minimizes the need for chemical fertilizers and pesticides.
b) It allows farmers to grow different crops on the same land sequentially.

47. List two characteristics each of roughage and concentrate in relation to animal feed. [2 Marks]

Answer:
1. Roughage: It is rich in fibre and contains relatively low levels of nutrients.
2. Concentrate: It is low in fibre and contains high levels of proteins and other nutrients.

Teacher's Note:
a) Roughage includes green fodder, silage, and hay.
b) Concentrates include oilseed cakes and grains.

48. Mention the two types of food requirements of dairy animals. [2 Marks]

Answer:
1. Maintenance requirement - food needed to support the animal to live a healthy life.
2. Milk-producing requirement - food needed during the lactation period to sustain milk production.

Teacher's Note:
a) A proper balance of nutrients prevents nutritional deficiency diseases.
b) This is a repeated question verifying basic dairy management concepts.

49. "Removal of weeds from cultivated fields during the early stages of growth of crops is essential for a good harvest". Justify the statement. [3 Marks]

Answer:
1. Weeds compete with main crops for essential resources like sunlight, water, nutrients, and space.
2. Early removal prevents weeds from stunting crop growth and reducing overall yield.
3. Unchecked weeds can also harbour pests and diseases that affect the main crop.

Teacher's Note:
a) Weeds are unwanted plants growing alongside cultivated crops.
b) Early weeding ensures the crop gets maximum nourishment during its critical growth phase.
c) Mechanical removal, weedicides, and cultural practices are common weeding methods.

50. Farmers use bee-keeping as an additional income generating activity. Give two reasons. [2 Marks]

Answer:
1. It produces honey, which has high commercial value and market demand.
2. It yields beeswax, which is widely used in various industries like cosmetics and pharmacy.

Teacher's Note:
a) Bee-keeping requires low initial investment.
b) Bees also act as pollinators, helping improve crop yields in nearby fields.

51. Name any one bottom feeder that can be grown in composite fish culture. [1 Mark]

Answer:
1. Common carp is a bottom feeder used in composite fish culture.

Teacher's Note:
a) Composite fish culture uses five to six species with different food habits in a single pond.
b) Bottom feeders feed on detritus and decaying organic matter at the floor of the pond.

52. What are the problems faced in such a culture ? How are they overcome? [2 Marks]

Answer:
1. Problem: Many fish species breed only during monsoon and lack of good quality fish seed.
2. Solution: Hormonal stimulation is used to breed these fish in ponds and ensure a supply of pure fish seed.

Teacher's Note:
a) Composite fish culture maximizes fish yield from a single water body.
b) Different feeding zones ensure there is no food competition among species.

53. The shorter the duration of the crop the more economical is the variety. Justify this statement. [3 Marks]

Answer:
1. Short-duration crops reduce the cost of crop production through less water and fertilizer usage.
2. It allows farmers to grow multiple crops on the same piece of land within a single year.
3. It minimizes the risk of crop damage from unfavorable weather conditions or pests.

Teacher's Note:
a) Crop duration refers to the time taken from sowing to harvesting.
b) Economic viability is a key goal in modern agricultural practices.
c) Plant breeding aims to develop high-yielding, short-duration varieties.

54. What are the long term benefits of using manure in crop production? [3 Marks]

Answer:
1. It replenishes organic matter in the soil, improving its overall structure.
2. It enhances the water-holding capacity of sandy soils and drainage in clayey soils.
3. It promotes the growth of friendly soil microbes that provide nutrients to plants.

Teacher's Note:
a) Manure is prepared from animal excreta and plant waste.
b) Unlike chemical fertilizers, manure does not cause chemical toxicity or water pollution.
c) Long-term soil health depends on maintaining adequate organic matter.

55. What is the major problem is fish farming? How is this problem overcome? [2 Marks]

Answer:
1. Problem: Lack of availability of good quality seed (fish eggs/fry) because many fish breed only during monsoons.
2. Overcome: By using hormonal stimulation to breed fish in ponds, ensuring a continuous supply of pure fish seed.

Teacher's Note:
a) Seed availability is critical for commercial fish farming.
b) Induced breeding techniques have revolutionized aquaculture.

56. How can insect/pests in crop plants and stored grains be controlled? [3 Marks]

Answer:
1. Using pesticides, insecticides, and fungicides for standing crops.
2. Applying strict sanitation, proper drying, and fumigation in storage godowns.
3. Adopting resistant crop varieties and crop rotation practices.

Teacher's Note:
a) Pests cause severe quantitative and qualitative losses.
b) Preventive measures are always preferred over chemical treatments.
c) Proper moisture control is vital during grain storage.

57. What is meant by the term 'green manure'? State its role in agriculture. [2 Marks]

Answer:
1. Green manure refers to green plants grown and ploughed back into the soil to enrich it with nutrients.
2. Its role is to supply nitrogen and phosphorus and improve soil structure and organic matter.

Teacher's Note:
a) Sunn hemp or guar are commonly used as green manure crops.
b) It helps suppress weed growth and prevents soil erosion.

58. How is green manuring done? How is it useful for the soil? [2 Marks]

Answer:
1. Quick-growing plants are grown before sowing crop seeds, mulched by ploughing them into the soil.
2. It enriches the soil with nitrogen and phosphorus, improving fertility and water retention.

Teacher's Note:
a) Decomposition of green plants releases essential nutrients.
b) It represents an eco-friendly alternative to chemical fertilizers.

59. What is pasturage and has how is it related to honey production? [2 Marks]

Answer:
1. Pasturage is the availability of flowers accessible to bees for nectar and pollen collection.
2. It determines the taste, quality, and quantity of honey produced.

Teacher's Note:
a) Different flowers yield nectar with different flavour profiles.
b) Adequate pasturage near apiaries ensures high honey yields.

60. What are Rabi and Kharif crops? Give two examples each. [3 Marks]

Answer:
1. Kharif crops are grown during the rainy season (June to October). Examples: Paddy and maize.
2. Rabi crops are grown during the winter season (November to April). Examples: Wheat and gram.

Teacher's Note:
a) Cropping seasons depend heavily on monsoon patterns in India.
b) Different crops have distinct temperature and water requirements.
c) Soybean and cotton are other examples of Kharif crops.

61. Name two biotic and two abiotic factors that affects crop production. [2 Marks]

Answer:
1. Biotic factors: Pests, insects, nematodes, and weeds (any two).
2. Abiotic factors: Temperature, water, salinity, and wind (any two).

Teacher's Note:
a) Both factor types can severely damage crops and lower yields.
b) Resistant varieties help combat biotic stresses.

62. What is meant by organic farming? [2 Marks]

Answer:
1. Organic farming is a farming system with minimal or no use of chemical fertilizers, pesticides, and herbicides.
2. It maximizes the use of organic manures, recycled farm wastes, bio-agents, and crop rotation.

Teacher's Note:
a) It promotes sustainable agriculture and protects environmental health.
b) It maintains long-term soil fertility and biodiversity.

63. Compare the use of manure and fertilizers in maintaining soil fertility. [3 Marks]

Answer:
1. Manure supplies organic matter (humus) to the soil, which improves soil structure, water retention capacity, and aeration, whereas fertilizers do not add humus to the soil.
2. Manure is relatively less rich in plant nutrients and releases them slowly, whereas fertilizers are commercially produced plant nutrients rich in nitrogen, phosphorus, and potassium that provide immediate nourishment.
3. Continuous use of manure improves long-term soil fertility and sustains soil health, whereas excessive use of fertilizers can destroy soil texture and fertility over time by killing beneficial soil microbes.

Teacher's Note:
a) Manure is a natural substance obtained from the decomposition of animal wastes and plant residue.
b) Fertilizers are inorganic chemical compounds produced industrially.
c) Emphasize that organic farming relies heavily on manure to maintain ecological balance.

64. What is meant by sustainable agriculture? [2 Marks]

Answer:
1. Sustainable agriculture refers to the successful management of resources for agriculture to satisfy changing human needs while maintaining or enhancing the quality of the environment.
2. It aims to conserve natural resources such as soil, water, and plant/animal genetic resources without causing environmental degradation.

Teacher's Note:
a) It integrates agricultural production with environmental conservation.
b) Practices like mixed farming, crop rotation, and integrated pest management support sustainability.

65. What are macronutrients and why are they named so? Give examples also. [3 Marks]

Answer:
1. Macronutrients are essential chemical elements that are required by plants in large quantities for their growth and development.
2. They are named so because plants consume them in relatively large amounts compared to other nutrients.
3. Examples of macronutrients include nitrogen, phosphorus, potassium, calcium, magnesium, and sulphur.

Teacher's Note:
a) Plants absorb nutrients mainly from the soil through their root systems.
b) Out of 16 essential nutrients, 6 are classified as macronutrients.
c) Nitrogen and phosphorus are primary macronutrients heavily utilized during vegetative growth.

66. Which component of food is present in pulses ? Also mention its function in the body. [2 Marks]

Answer:
1. Proteins are the major component of food present in pulses.
2. Proteins function as body-building foods that are essential for growth, tissue repair, and the formation of enzymes and hormones.

Teacher's Note:
a) Pulses serve as a primary source of vegetarian protein.
b) Adequate protein intake is vital for maintaining a healthy immune system.

67. Define-green manure and vermicompost. [2 Marks]

Answer:
1. Green manure refers to green plants that are grown and plowed back into the soil to enrich it with nitrogen and phosphorus before sowing crop seeds.
2. Vermicompost is the organic fertilizer produced by the biological decomposition of organic wastes using earthworms.

Teacher's Note:
a) Sunn hemp or guar are common plants used as green manure.
b) Vermicomposting accelerates the breakdown of organic matter and enhances nutrient availability.

68. Differentiate between bee keeping and poultry farming. [3 Marks]

Answer:
1. Bee keeping (apiculture) is the practice of rearing, caring for, and managing honeybees on a large scale for obtaining honey and beeswax, whereas poultry farming involves raising domesticated birds like chicken, ducks, and turkeys for eggs and meat.
2. Bee keeping requires flowering flora and specialized wooden hives, whereas poultry farming requires ventilated shelters, proper lighting, and formulated feed.
3. The primary products in bee keeping are honey and wax, whereas the primary products in poultry farming are eggs and poultry meat (broilers).

Teacher's Note:
a) Both are important income-generating agricultural activities.
b) Apiculture also helps significantly in cross-pollination of crops.
c) Disease management is critical in both sectors to prevent massive stock loss.

69. Give two merits and two demerits of fish culture. [3 Marks]

Answer:
1. Merits: It yields a high production of fish in a small area through composite fish culture, and it provides a rich source of cheap animal protein and employment opportunities.
2. Demerits: It requires constant monitoring of water quality parameters, and fish stocks are highly susceptible to widespread communicable diseases and water pollution.

Teacher's Note:
a) Composite fish culture uses five to six species together in a single pond without competing for food.
b) Surface feeders, column feeders, and bottom feeders are stocked simultaneously.
c) Water quality management is the most critical factor determining success.

70. Suggest two preventive measures for the diseases of poultry birds. [2 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 infections to build immunity.

Teacher's Note:
a) Prevention is more cost-effective than treatment in poultry farming.
b) Providing clean drinking water and uncontaminated feed prevents parasitic outbreaks.

71. List out four useful traits in improved crop? [2 Marks]

Answer:
1. Higher yield.
2. Improved quality.
3. Biotic and abiotic resistance.
4. Desirable agronomic traits.

Teacher's Note:
a) Crop improvement aims to develop varieties with high economic return.
b) Resistance to pests and drought ensures food security under adverse climatic conditions.

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

Answer:
1. A Genetically Modified (GM) crop is a plant whose DNA has been altered using genetic engineering techniques to introduce desirable traits.
2. Bt cotton is a well-known GM crop grown in India.

Teacher's Note:
a) Bt cotton contains a gene from the bacterium Bacillus thuringiensis that produces a toxin against bollworms.
b) GM crops help reduce pesticide usage and increase overall productivity.

73. Define the term photoperiod. [1 Mark]

Answer:
1. Photoperiod refers to the duration of daily exposure to sunlight that influences plant growth, development, and flowering.

Teacher's Note:
a) Flowering in many plants is dependent on the duration of light periods.

74. Group the following and tabulate them as energy yielding, protein yielding, oil yielding and fodder crop. [3 Marks]

Answer:

Teacher's Note:
a) Cereals provide carbohydrates for energy.
b) Pulses provide essential proteins.
c) Oilseeds provide necessary fats and fatty acids.

75. What type of crops are generally raised in green fields? [1 Mark]

Answer:
1. Fodder crops and green manure crops are generally raised in green fields.

Teacher's Note:
a) These crops supply green biomass and nutrition to livestock or soil.

76. Write four points on human dependence on plants and animals for food. [2 Marks]

Answer:
1. Plants provide cereals, pulses, vegetables, and fruits which supply carbohydrates, proteins, vitamins, and minerals.
2. Plants serve as primary producers forming the base of all food chains.
3. Animals provide milk, eggs, meat, and honey which are rich sources of animal proteins and fats.
4. Both plant and animal sources are essential for fulfilling the nutritional requirements of the human body.

Teacher's Note:
a) Human survival depends directly on agriculture and animal husbandry.
b) A balanced diet requires a combination of both plant and animal-based foods.

77. Distinguish between intercropping and mixed cropping. List any two advantages of intercropping over mixed cropping. [3 Marks]

Answer:
1. Mixed cropping involves growing two or more crops simultaneously on the same land without a definite row pattern, whereas intercropping involves growing two or more crops simultaneously in a definite row pattern (such as 1:1 or 1:2).
2. Advantage 1: The seeds of the two crops are not mixed before sowing in intercropping, allowing fertilizers and pesticides to be applied selectively.
3. Advantage 2: Harvesting and threshing of the two crops can be done separately due to the definite row arrangement, unlike mixed cropping.

Teacher's Note:
a) Both methods aim to minimize crop failure risk.
b) Intercropping maximizes resource utilization like light and nutrients.
c) Pest control is significantly easier in intercropping.

78. State three management practices that are common in dairy and poultry farming. [3 Marks]

Answer:
1. Proper shelter management involving clean, spacious, and well-ventilated housing.
2. Regular feeding practices with nutritious and balanced diet formulations.
3. Disease control and prevention through hygiene maintenance and timely vaccination.

Teacher's Note:
a) Animal husbandry requires strict sanitary conditions.
b) Prevention of parasitic infestations improves overall yield.
c) Record keeping is another common administrative practice.

79. List any three desirable characters of bee varieties suitable for honey production? [3 Marks]

Answer:
1. They should yield high quantities of honey.
2. They should sting less and stay docile in the hive.
3. They should stay in a given beehive for longer periods and breed very well.

Teacher's Note:
a) Apis mellifera is commonly preferred due to these traits.
b) Gentle behavior prevents frequent attacks on apiary workers.
c) Swarming tendency should be minimal.

80. List any three ways by which the insect/pests attack the plants. [3 Marks]

Answer:
1. Chewing insects cut and consume plant roots, stems, and leaves.
2. Sucking insects suck cell sap from various plant parts using their needle-like mouthparts.
3. Borers bore into stems and fruits, damaging internal tissues and destroying the crop.

Teacher's Note:
a) Pests can drastically reduce agricultural yields if left uncontrolled.
b) Different pests target specific parts of the plant.
c) Identification of pest attack mode helps in selecting appropriate pesticides.

81. List any three desirable characters of bee varieties suitable for honey production? [3 Marks]

Answer:
1. They should have high honey-gathering capacity.
2. They should be gentle in temperament and sting less.
3. They should show good breeding capacity and disease resistance.

Teacher's Note:
a) This question is a repetition of Q. 79 from the source paper.
b) Selection of the right bee strain ensures commercial viability of apiculture.
c) Italian bee varieties are widely used for commercial production.

82. List any six factors for which variety improvement in crops is done. [4 Marks]

Answer:
1. Higher crop yield per unit area.
2. Improved nutritional quality of the produce.
3. Biotic resistance against pests, insects, and diseases.
4. Abiotic resistance against drought, salinity, heat, and cold.
5. Desirable agronomic characteristics like dwarfness in cereals.
6. Change in maturity duration for multiple cropping patterns.

Teacher's Note:
a) Crop variety improvement is achieved through hybridization and genetic modification.
b) Shorter maturity duration reduces cost and allows multiple harvests per year.
c) Lodging resistance is an important agronomic trait.
d) Developing stress-tolerant varieties secures food supply against climate change.