Important Questions for CBSE Class 9 Science Improvement in Food Resources

Improvement In Food Resources Class 9 Important Questions for Science Chapter 15

Science is an exciting subject with a vast syllabus and requires adequate preparation. The subject is the building block, especially for those students who want to pursue careers in Medicine, Pharmacy, Engineering, Biotechnology, etc. 

Chapter 15 of Class 9 Science is about ‘Improvement in Food Resources’. The chapter includes topics such as food sustainability, crop production, pesticide, environmental impact, genetic modification, etc. 

Extramarks is one of the leading online educational platforms offering the best study materials to students across the country. The chapter notes prepared by our subject matter experts provide an in-depth understanding of the topics. The study material engages students with interactive learning, knowledge, and conceptual preparation through guided practice and helps to get the best results.

Extramarks completely understand the importance of subject revision and practice through solving chapter questions. To facilitate this our experienced Science faculty members have collated a questionnaire consisting of Important Questions Class 9 Science Chapter 15. The questions are carefully chosen from various resources such as the NCERT textbook, NCERT exemplar, CBSE past years’ question paper, and other Science reference books. The answers given to these questions are accurate, to the point and reliable  and help students to revise the chapter fully. 

Our repository of chapter 15 class 9 science important questions and the associated solved answers offer comprehensive coverage of all the essential topics for class assessment, tests , annual exams  and competitive exams. These solutions are based on the latest NCERT exam guidelines and increase students familiarity with the format of questions and answers  expected  in their exams.

Along with Important Questions Class 9 Science Chapter 15, students will find a host  of other study resources such as NCERT  solutions,  CBSE sample papers, CBSE chapter-wise notes, CBSE revision notes, etc. Visit the Extramarks website to enjoy a host of study materials available at the website for ready reference.

Get Access to CBSE Class 9 Science Important Questions 2022-23 with Solutions

Also, get access to CBSE Class 9 Science Important Questions for other chapters too:

CBSE Class 9 Science Important Questions
Sr No Chapters Chapter Name
1 Chapter 1 Matter in Our Surroundings
2 Chapter 2 Is Matter Around Us Pure
3 Chapter 3 Atoms and Molecules
4 Chapter 4 Structure of Atom
5 Chapter 5 The Fundamental Unit of Life
6 Chapter 6 Tissues
7 Chapter 7 Diversity in Living Organisms
8 Chapter 8 Motion
9 Chapter 9 Force and Laws of Motion
10 Chapter 10 Gravitation
11 Chapter 11 Work and Energy
12 Chapter 12 Sound
13 Chapter 13 Why Do We Fall ill
14 Chapter 14 Natural Resources
15 Chapter 15 Improvement in Food Resources

CBSE Class 9 Science Chapter 15 Question Answer

The questions are carefully designed in our question bank of Class 9 Science Chapter 15 Important Questions. It has a variety of question formats, including MCQs, fill in the blanks, short and long answer questions, etc. strictly  following the pattern of board exams.

Below are a set of few questions and their answers from our Science Class 9 Chapter 15 Important Questions. Students can register on our website and get access to a complete list of these important questions.

Question 1. What do we obtain from cereals, pulses, fruits and vegetables?

Answer 1: Cereals like wheat, rice, and maize are the sources of carbohydrates, and they provide energy to our bodies. Pulses like peas, gram, soybean, etc., are a rich source of proteins. In addition to protein and carbohydrates, our body also requires vitamins and minerals in small quantities, which are provided by fruits and vegetables.

Question 2. How is crop production affected by biotic and abiotic factors?

Answer 2: Biotic factors like pests, insects and rodents cause loss of grains. Cold, heat, drought, salinity, water logging and frost are the abiotic factors which stress crops and adversely affect crop production.

These biotic and abiotic factors cause poor seed germination,  weeds,insects and diseases, low yield and discolouration of leaves.

Question 3. Mention desirable agronomic characteristics for crop improvement.

Answer 3: Higher productivity of crop plants is attributed to desirable agronomic traits. Food crops have desirable tallness and profuse  branching. Tall crops cannot resist strong winds, so dwarfness is desirable in cereals.

Question 4. Explain macronutrients.

Answer 4: Macronutrients are those essential nutrients which plants require for their growth, survival and functioning. They are called macronutrients because they are required in large quantities  by them. The macronutrients needed by the plants are:

  • Nitrogen
  • Calcium
  • Phosphorus
  • Potassium
  • Magnesium
  • Sulphur 

Question 5. How do plants get nutrients?

Answer 5: The nutrients the plants require are supplied by  the soil, and the roots absorb them. Carbon, oxygen and hydrogen are those nutrients provided by  air and water.

Question 6. Compare the use of manures and fertilizers in maintaining soil fertility

Answer 6: Manures and fertilizer improve soil fertility and enhance crop productivity. Both of them replenish the nutritional deficiency in the soil. 

Manures are the sources of soil organisms. Soil-friendly bacteria are present in the manure. Manures provide humus to the soil. Humus is an organic matter which restores the water retention capacity of sandy soils and drainage in clayey soils.

Fertilizers can cause damage to the soil when they are used in excess amounts. They make the soil dry and increase the rate of soil erosion. The organic matter decreases due to the continuous use of fertilizers. They also reduce soil fertility. When the soil’s pores  reduce, the plant’s roots do not get sufficient oxygen.

Question 7. Which of the following conditions give the maximum benefits and why?

  1. Farmers use high-quality seeds and do not adopt irrigation or use fertilizers.
  2. Farmers use ordinary seeds, use irrigation and use fertilizers.
  3. Farmers use quality seeds, adopt irrigation, use fertilizers and use crop protection measures.

Answer 7:

 The last option (3)provides the most benefits because of the following reasons:

  • When the farmers use high-quality seeds, it gives a good yield.
  • Adopting irrigation methods will overcome drought and flood situations.
  • Fertilizers will fulfil the nutritional requirements of the soil. High yield will be obtained following the use of fertilizers..
  • Using crop protection measures will protect the plants from pests, pathogens and weeds.
  • This concludes that farmers will benefit significantly from using good seeds and agronomic approaches.

Question 8. Why preventive measures and biological control methods are preferred for crop protection?

Answer 8: The following reasons are preferred for using preventive and biological methods in protecting crops:

  • The ways are simple and specific to the target.
  • They are economical because there is a less financial investment.
  • They are ecologically friendly as they minimize pollution.
  • They do not affect soil fertility.
  • They do not cause harm to other living organisms.

Question 9. What are the biotic and abiotic factors that cause loss of grain during storage?

Answer 9: The biotic and abiotic factors that cause  loss of grain during storage are: 

  • They attack insects, rodents, fungi, mites and bacteria.
  • Presence of inappropriate moisture and temperature in the storage place.

Question 10. Which method improves cattle breeding and why?

Answer 10: Cross-breeding improves cattle breeds. The indigenous varieties of the cattle are crossed with the exotic species, and a cross-breed of desired quality is obtained.

Question 11. Multiple choice questions:

  • Weeds affect crop plants by 
  1. Killing plants before their growth.
  2. Dominating the plants to grow.
  3. Competing for resources of crops causes low availability of nutrients.
  4. All of the above

Answer 11: 

  1. A) Option 4: All of the above.

Weeds are unwanted plants. They compete with main crops for nutrition and affect their growth. Their seeds germinate easily and grow faster. They also flower earlier, and seed production occurs earlier. Many seeds are produced.

B) Preventive and control measures adopted for the storage of grains include

  1. Strict cleaning
  2. Proper disjoining
  3. Fumigation
  4. All of these


B) Option 4: All of these. The grains are stored in godowns, warehouses and stores. These should be cleaned, dried and repaired to keep grains.

  1. C) Which of the following fish is a surface feeder?
  2. Rohus
  3. Mrigals
  4. Common carp
  5. Catlas

C) Option 2, 3: Surface feeders have a straight back, allowing their upturned mouths to quickly reach  the surface and scoop  the food. Catlas possess these characteristics of surface feeders. Rohus feeds in the middle zone of the ponds. Mrigals and common carps are the bottom feeders.

Question 12: Fill in the blanks:

  1. Farming without the use of chemicals such as fertilizers, herbicides and pesticides is called __________
  2. Growing wheat and groundnut on the same field is called _________
  3. Planting soybean and maize in alternate rows in the same field is called ________
  4. Growing different crops on a piece of land in pre-planned succession is known as _______
  5. Xanthium and Parthenium are commonly known as ________
  6. Causal organisms of any disease are called ___________

Answer 12:

  1. Farming without the use of chemicals such as fertilizers, herbicides and pesticides is called organic farming.
  2. Growing wheat and groundnut on the same field is called mixed cropping
  3. Planting soybean and maize in alternate rows in the same area is called intercropping.
  4. Growing different crops on land in pre-planned succession is known as crop rotation.
  5. Xanthium and Parthenium are commonly known as weeds.
  6. Causal organisms of any disease are called pathogens.

Question 13. What is pasturage, and how is it related to honey production?

Answer 13: Pasturage is the flowering plants and trees found around an apiary. From these, bees collect nectar and pollen to form honey.

Pasturage is essential to determine the quality and quantity of honey. This is because the quality of honey depends upon the pasturage, while the type of flowers determines the taste of honey.

Question 14. How are fishes obtained? What are the advantages of composite fish culture?

Answer 14: The fish are obtained by capture fishing and culture fishery.

Capture fishing means fish are captured from their natural resources. Culturing of fish by fish farming is called Culture fishery.

The advantages of composite fish culture are:

  • In composite fish culture, the competition for food between the fish is avoided.
  • All the species consume the food in the pond without any competition.
  • Total fish yield from the pond increases.

Question 15. What are the desirable bee varieties for honey production?

Answer 15: The desired characteristics are:

  • The bees should have good honey production capacity.
  • The bees should be stingless.
  • They should breed very well.
  • They should have the ability to stay in a beehive for long periods.

Question 16. Which management practices are standard in dairy and poultry farming?

Answer 16: The common management practices include:

  • A well-designed, ventilated and hygienic shelter.
  • Balanced nutrition is provided to both birds and animals.
  • Regular check-ups.
  • Protection against diseases.

Question 17. What is the difference between broilers and layers and their management?

Answer 17: A broiler is a poultry bird kept for obtaining meat, whereas a layer is a poultry bird which gives eggs. A difference lies in their housing, nutrition and environment.

Broilers require a protein-rich diet with sufficient fat and good quality Vitamin A and K.

Layers require vitamins, minerals and nutrients with good space and proper lighting.

Question 18. Explain one method of crop production which ensure high yield. Mention the advantages of the technique.

Answer 18: Intercropping is one such method which provides a high yield. In this method, two or more crops which have different nutritional requirements are grown  simultaneously in a definite pattern. The advantages of intercropping include:

  • The method ensures maximum utilization of the supplied nutrients.
  • It aids in disease control also. This is because this method prevents pests and diseases from spreading to all the crops. This is because the disease belongs to one crop in a field, and in intercropping, there are two or more crops.

Question 19. What are the advantages of crop rotation?

Answer 19: The advantages of crop rotation are:

  • Increase in soil fertility.
  • Increase in crop yield from a single field.
  • Reduction in usage of fertilizers.
  • Leguminous plants are grown in crop rotation to help in nitrogen fixation, so nitrogen fertilizer is not required.
  • The crop rotation replenishes the fertility of the soil.

Question 20. What is genetic manipulation, and how is it useful in agricultural practices?

Answer 20: Genetic manipulation is the addition and incorporation of the desirable characteristic in an organism by the process of hybridization, mutation, DNA recombination, etc.

The scope of genetic manipulation in agricultural practices is:

  • Improvement in varieties of seed.
  • High yield.
  • Better adaptation.
  • Disease resistance.

Question 21. How do farmers benefit from good animal husbandry practices?

Answer 21: The benefits of good animal husbandry practices are:

  • It involves the scientific management of farm animals.
  • Improvement of breeds with good, desirable characteristics.
  • A yield with good quality and quantity.
  • Input cost is reduced.

Question 22. What are the benefits of cattle farming?

Answer 22: Cattle provide us with milk and milk-based products. Cattles do labour work in fields for tilling, irrigation and carting.

Question 23. Differentiate between capture fishing, mariculture and aquaculture?

Answer 23: 

Capture fishing Mariculture Aquaculture
Fish is obtained from natural resources like rivers, ponds and canals. Practice of culturing marine fish varieties in the coastal waters. It is the production of fish from freshwater resources.
Fishes are located easily and caught with a net. Satellites and echo-sounders are used for locating large fish schools. Fishes can be located easily and can be caught using simple fishing nets.

Question 24. Group the following and tabulate them as energy-yielding, protein-yielding, oil-yielding, and fodder crops. Wheat, rice, berseem, maize, oat, pigeon, sudangrass, lentil, soybean, groundnut, castor and mustard.

Answer 24:

  • High-yielding crops are rice, wheat, maize and oats.
  • Protein-yielding crops are gram, lentil, and pigeon gram.
  • Oil-yielding crops are groundnut, castor, soybean and mustard.
  • Fodder crops are berseem and Sudan grass.

Question 25. Discuss the role of hybridization in crop improvement.

Answer 25: Hybridization is a process by which genetically dissimilar crops are crossed. It is of three types: intervarietal, interspecific and intergeneric cross.

The Intervarietal cross is the crossing between two different varieties. It is done to improve the variety of the crop. This produces a high-yielding crop which is resistant to diseases and pests. Their quality is improved and plays a significant role in crop improvement.

 Crossing between two different species of the same generic is called an interspecific cross. The intergeneric cross is between different genera.

Question 26. In agriculture practices, higher input gives a higher yield. Discuss how.

Answer 26: When high-yielding varieties, modern techniques, and improved farm practices with the latest agricultural machines are used, then high yielding can be obtained. These require cost and knowledge. Finance is very important as it decides the output and the outcome of cropping. So higher input means high yields.

Question 27. Differentiate between compost and vermicompost.

Answer 27:

Compost Vermicompost
Compost is prepared from organic waste. Vermicompost is prepared from domestic waste.
It is prepared from sewage, animal refuse, farm waste, etc. It is prepared from vegetable waste, etc.
Takes 3 to 6 months to prepare. Take 1 to 2 months to prepare.
Microbes decompose organic remains. Earthworms pulverize organic remains.

Question 28. Briefly discuss the following:

  1. Vermicompost.
  2. Green manure
  3. Biofertilizers.

Answer 28:

  1. Vermicompost is manure rich in pulverized organic matter and nutrients. The compost is prepared using earthworms to hasten the decomposition process of plants and animals refuse.
  2. Green manure is prepared by growing green plants in the field itself. It enriches the soil with nitrogen and phosphorus content. For example, sun hemp is grown in areas, mulched by ploughing and allowed to decompose in the field to prepare the green manure.
  3. Biofertilizers are living organisms used as fertilizers to supply nutrients to crop plants. Nitrogen-fixing blue-green algae and nitrogen-fixing bacteria fix the nitrogen in the soil.

Question 29. If there is low rainfall in a village throughout the year, what measures will you suggest to the farmers for better cropping?

Answer 29: The measures for better cropping are:

  • Enrich the soil with humus. It increases the water holding capacity of the soil.
  • Reduces tilling.
  • Use of drought-resistant varieties of crops.
  • To grow early maturing varieties of crops.
  • Better irrigation facilities.
  • Methods to conserve water.

Question 30. What is the significance of animal husbandry?

Answer 30: The significance is to improve the breeds of domesticated animals and to increase the yield of foodstuffs like milk, egg and meat.

Question 31. What are the methods of weed control?

Answer 31: The various methods are:

A mechanical way of weed control is:

  • Uprooting
  • Weeding
  • Ploughing
  • Burying
  • Flooding

Cultural methods of weed control are:

  • Proper seedbed preparation
  • Sowing of crops timely
  • Intercropping
  • Crop rotation.

Chemical methods of weed control are:

  • Herbicide spraying
  • Weedicide.

Biological control of weed control are:

  • Use of insects to destroy weeds.
  • Insects control Opuntia.
  • Aquatic weeds are controlled by grass carp.

Question 32. Discuss why pesticides should be used in very accurate concentration and in a very appropriate manner.

Answer 32: This is because of the following reasons:

  • Pesticides are harmful to the environment.
  • They are non-biodegradable.
  • They can cause biomagnification. They can accumulate in organisms.
  • They adversely affect the non-target species as they are sprayed and reach areas other than the target species.
  • Run-off can carry pesticides into aquatic bodies.
  • Wind can carry the pesticides to the areas of human settlement, fields and grazing areas.
  • They affect other species.
  • They harm the soil and reduce its fertility.
  • They kill the beneficial microorganisms of the soil.
  • They pass into the groundwater to make it toxic.
  • They also enter the crop plants and make them harmful.
  • They may pass into the surface water and harm aquatic organisms.
  • Other problems are due to storage, transport and poor production.

Question 33. Mention preventive measures for the diseases of poultry birds.

Answer 33: Poultry birds suffer from many diseases. These affect the growth, quality and quantity of the chicks.. The measures to control the disease are:

  • To provide adequate nutrition to the poultry birds.
  • To keep birds in a good spacious, airy and ventilated shelter.
  • Their shelter should be cleaned. Quick disposal of excreta.
  • Proper sanitation.
  • Timely vaccination.
  • Spraying disinfectant regularly in the shelter to kill mosquitoes and other parasites.
  • External parasites can be controlled by applying insecticide solutions.

Question 34. An Italian bee variety, Apis mellifera, has been introduced in India for honey production. Write about its merit over the other varieties.

Answer 34: The advantages of this Italian bee include:

  • These bees are stingless.
  • They stay in beehives for more extended periods.
  • They breed very well.
  • The honey collection capacity is high.

Question 35. Differentiate between capture and culture fishery.

Answer 35:

Capture fishery Culture fishery
Way of obtaining fish from natural resources. Fish farming is done to obtain fish.
No seeding and raising of the fish. Rearing of fish is involved.
Undertaken in both inland and marine waters. The culture fishery is undertaken mostly inland and near the seashore.

Question 36. Differentiate between bee-keeping and poultry farming.

Answer 36:

            Bee-keeping         Poultry farming
Beekeeping involves the rearing and management of honeybees. This is the process of raising domestic fowl.
Honey-bees obtain food from flowers or nectar. Poultry birds are provided food by the rearers.
Provides honey, wax, etc. Provides eggs and meat.

Question 37. How does a deficiency of essential nutrients affect the growth of plants?

Answer 37: Plants require 16 essential nutrients. When there is a deficiency of these essential nutrients, the physiological process is affected, and there is a disturbance in plants’ growth, development and reproduction. The disease also increases the susceptibility to disease. To fulfil these nutritional requirements, manure and fertilizers are used.

Question 38. What do you understand about the composite fish culture? Describe its advantages and disadvantages.

Answer 38:

Composite fish culture is adopted for intensive fishing.

The characteristics are:

  • Both local and imported fish are used.
  • In a single fish pond, 5 to 6 species of fish can be used.
  • These species have different feeding habits.
  • They are the selected species so there is no competition for food.

The advantages are:

  • All the food available in the pond is utilized.
  • There is no competition for food.
  • There is an increase in the fish yield from the pond.

The disadvantage includes:

  • The lack of availability of good quality fish seeds.

Question 39. What would happen if poultry birds had large size and no summer adaptation capacity? What method would be employed to get small-sized poultry birds having summer adaptability?

Answer 39: More feed is required by the large-sized birds. Summer adaptation is connected with egg laying. Little summer adaptation reduces egg laying.

To obtain small-sized poultry birds having summer adaptability, it is desirable to introduce exotic birds from the outside. Cross breeding the local birds with exotic birds from outside is also desirable.

Small-sized birds are preferred for

  • Lower requirement of feed.
  • Higher egg-laying capacity.
  • Lower need for space.

Question 40. Name the types of animal feed and write their function.

Answer 40: Animal feed is the food provided to the animal. Its types are:

  • Roughage is a coarse and fibrous food with a low level of nutrition. It includes green fodder, silage, hay and legumes.
  • Concentrates are those substances which are rich in one or more nutrients. Examples are cotton seeds, oil seeds, cakes, bajra and gram.

Question 41. Mention the advantages and disadvantages of fish culture.

Answer 41: The advantages of fish culture includes obtaining a large amount of desired fishes in a small area. There are chances of making improvements in fish cultivation.

Fish culture is a threat to biodiversity. Only ecologically important and valued fishes can be cultured. These are the drawbacks of the fish culture.

Question 42. Fill in the blanks:

  1. Pigeon pea is a good source of __________
  2. Berseem is an important _________ crop.
  3. The crop which is grown in the rainy season is called ________ crops.
  4. _________are rich in vitamins.
  5. __________ crop grows in winter season.
  6. Photoperiod affect the __________
  7. Kharif crops are cultivated from _______.
  8. Rabi crops are produced from __________.
  9. Paddy, maize, green gram and black gram are examples of _________crops.
  10. Wheat, gram, pea, and mustard are _______

Answer 42:

  1. Pigeon pea is a good source of protein.
  2. Berseem is an important fodder crop.
  3. The crop which is grown in the rainy season is called Kharif crops.
  4. Vegetables are rich in vitamins.
  5. Rabi crop grows in the winter season.
  6. Photoperiods affect the flowering of plants.
  7. Kharif crops are cultivated in June or October.
  8. Rabi crops are produced from November to April.
  9. Paddy, maize, green gram and black gram are examples of  Kharif crops.
  10. Wheat, gram, pea, and mustard are rabi crops.

Question 43. Why is excessive use of fertilizers harmful to the environment?

Answer 43: The excessive use of fertilizers causes:

  • Environmental pollution.
  • Excess minerals in crop plants.
  • Salination of soil.
  • Eutrophication of water bodies.

Question 44. 

  1. Difference between mixed cropping and intercropping with examples.
  2. How does crop rotation differ between the two?
  3. Mention the factors considered in deciding crops for intercropping and crop rotation with advantages. 

Answer 44.

  1. Difference between mixed cropping and intercropping 
Mixed cropping Intercropping 
Mixed cropping has a target to minimise the risk of crop failure. Intercropping has a target to increase productivity per unit area.
Seeds of two crops are mixed from sowing. Intercropping does not involve the mixing of two seeds.
It involves no set pattern of rows of crops. It involves a pattern of rows of crops.
It is difficult to individually apply fertilizer to individual crops. Fertilizers can be applied on the basis of the needs of the crop.
Pest control by spraying is difficult for individual crops. Pesticides can be easily applied to individual crops.
Harvesting and threshing of crops are  not possible separately. Crops can be harvested and threshed separately.
Marketing and consumption of only mixed produce are possible. The product of each crop can be marketed and consumed separately.
Examples of mixed cropping are wheat and mustard. Examples of inter-cropping are soybean and maize.
  1. In crop rotation, different crops are planted successively on the same plot. In mixed cropping and intercropping, two or more crops are grown simultaneously on the same field.
  2. The selection of intercropping, the selection of crops, is based on the different nutrition requirements.

The selection of crops in crop rotation is based on the availability of moisture and irrigation facilities.

The advantages are:

  • Intercropping ensures that the nutrients supplied are utilized.
  • Mixed cropping decreases crop failure due to uncertain monsoons.
  • Crop rotation increases soil fertility and hence enhances production.

Question 45. 

  1. How many nutrients are essential for plants?
  2. What are macronutrients and micronutrients?
  3. List the nutrients supplied by the air, water and soil.

Answer 45:

  1. There are 16 nutrients which are required by the plants.
  2. Macronutrients are the essential elements utilized by plants in relatively large amounts. The six essential macronutrients are nitrogen, phosphorus, potassium, calcium, magnesium and sulphur.
  3. Air supplies carbon and oxygen. Water provides hydrogen and oxygen. Soil supplies macronutrients and micronutrients.

Question 46. How are genetically modified crops made? Explain their significance with suitable examples.

Answer 46: Genetically modified crops are those plants in which DNA has been modified using genetically engineered techniques. The aim of making such crops is to introduce a new trait which does not exist naturally in the species.

The genes are added or removed using the genetic engineering technique. In this, DNA from another species of a similar kingdom is bound to tiny particles of gold or tungsten, which are subsequently shot into the plant tissue under high pressure. When accelerated, these particles penetrate the cell wall and the membranes. The DNA is separated from the metal, and it is integrated into the plant DNA inside the nucleus.

The significance of the genetically modified crop is that it increases the yield of crops. This provides farmers with more income. With the increase in the growing population and the constant land area, 

these genetically modified crops have increased the possibility of feeding the growing population.

Question 47. Crop protection management includes protection from weeds, insects, pests and disease. Describe briefly how plants are protected from the above-mentioned unwanted agents.

Answer 47: A large number of weeds, pests and diseases infect the crops. They damage the crops if they are not controlled at the right time. Weeds are unwanted plants in cultivated fields. They have competition with the crops for food, light and space. They take up the nutrients, which enhances their growth and reduces the growth of the crops. The insect pests attack the crop in three ways:

  • They cut the root.
  • They suck the cell sap.
  • They bore into the stem and fruits.

In this way, they affect the health of the crops, and their yield is reduced. Bacteria, viruses and fungi cause diseases in plants.

Pesticides include the use of herbicide, insecticide and fungicide. They can control weeds, insects and diseases. They are sprayed on the crop plant.

Weeds can also be removed by the mechanical method.

The preventive methods of controlling weeds are proper seedbed preparation, timely sowing of the crop, intercropping, and crop rotation.

The preventive measures against pests include the use of resistant varieties and summer deep ploughing of land.

Question 48. List six factors for the improvement of crops.

Answer 48: The six factors are:

  • High yield: The crops with high yields are required to meet the needs of the growing population.
  • Disease resistance: the yield of the crops gets reduced by disease. So crops with disease resistance are important for variety improvement.
  • Response to fertilizer gives good yield.
  • Product quality always fetches a better price and is aimed by the farmer.
  • Water demand is essential. Low water-intensive characteristics help farmers to cultivate crops even in the non-rainy season.
  • Maturity is important. Crops which mature give yield early.

Question 49.

  1. Name two familiar sources for fish capturing.
  2. Why are mussels and shellfish cultivated?
  3. How can the demand for more fish be met on depletion of marine fish stock?
  4. How are marine fish caught?
  5. Name two marine fish cultured in seawater and of high economic value.

Answer 49:

  1. The two common sources from which the fish are captured are the natural resources, including sea, ocean and river. The second is fish farming in fresh water and marine water.
  2. Mussels have high nutritional value. They are a good source of vitamins and have desirable fatty acids that improve brain function. It also has zinc which boosts immunity. Shellfish is also a rich source of vitamins, minerals and fish oil, and it brings good revenue as seafood.
  3.  Mariculture is the practice which cultivating marine organisms for commercial purposes and meeting the increasing fish demand. Their advantages are:
  • Food and products give economic value.
  • Important for industrial fishing.
  • Farming of marine fish, prawns and shellfish is done in an open ocean or artificial ponds filled with seawater.

4. The various ways to catch fish are hand gathering, netting, spearfishing, angling and trapping. For commercial purposes, fishes are captured from high seas by long lines, gill nets, purse seines and bottom trawlers.

5. The marine fishes which have high economic value are

  • Bhetki
  • Mullets
  • Pearl spot

Question 50. The production of food from animal sources has increased in the last few decades. Justify this statement.

Answer 50: Food production from animal sources has increased due to the new techniques in animal breeding. Operation Flood and Silver Revolution have increased milk and egg production in the last two decades. The production of fish and meat has also increased.

India is ranked 2nd among the fish-producing countries. A total of 40 % of fish are obtained from the Indian Ocean.

Question 51. What are the desirable traits for which the improved varieties are developed by cross-breeding programmes between indigenous and exotic breeds in poultry? What are the advantages of exotic breeds?

Answer 51: The desirable traits are:

  • To improve the quality and number of chickens.
  • Dwarf broiler parent for commercial chick production.
  • Summer or adaptation capacity for tolerance to high temperature.
  • Low maintenance requirements.
  • Improvement in hen housed for egg production.
  • Reduction in the size of the layer with the ability to utilize a more fibrous diet formulated using agricultural by-products.

The following are the advantages of the exotic varieties:

  • They have small sizes.
  • Eat less.
  • They mature easily.
  • They have an excellent yielding capacity for more eggs and meat.

Question 52. How many types of honeybees are present in one colony? Mention their function.

Answer 52: There are three types of honeybees in one colony, namely, Queen, Drones and Workers. Queen lays both fertile and unfertile eggs. Drones are the male colonies which mate with the queen. 

Workers are the most active members as they have all the responsibilities. They are females which cannot reproduce. They collect nectar, pollen and propolis.

Question 53. 

  • Besides causing ill health and death, how do diseases affect dairy animals?
  • On a cattle farm, there are fifteen cattle. How you can differentiate between diseased and healthy cattle without any diagnostic test?
  • Cattle feed should include the right amount of concentrates. What do concentrates in cattle feed refer to?

Answer 53:

  1. The disease affects the quality of milk and egg. The production of egg, milk and meat is reduced in diseased dairy animals.
  2. The points of difference between diseased and healthy cattle are food consumption, behaviour, excreta and milk production.
  3. The concentration of fibre is low in concentrates, but they are rich in proteins and other nutrients.

Question 54. What are the desirable characteristics of bee varieties suitable for honey production?

Answer 54: The required characteristics are:

  • The bees should be gentle in nature means they should not sting much.
  • The honey collection capacity should be high.
  • Prolific queen production with less swarming.
  • The bees should be able to protect themselves from their enemies.

Question 55. How do storage grain losses occur?

Answer 55: Damage caused by rodents to stored and standing crops. They consume the crops and contaminate them with their urine, excreta, etc.

Birds eat food grains and contaminate them with feathers and excreta. Infestation by insects and microorganisms decreases the nutritive value of food grains and spoils them.

Enzymes present in meat, fruits and fish catalyse metabolic reactions and cause damage to them.

Benefits of solving Improvement in Food Resources Class 9 Extra Questions and Answers

The Extramarks website provides valuable educational sources for the student to ace their exam .. Science is a challenging subject and requires theoretical learning and practical concepts understanding to score good marks in the exam. Regularly revising chapter notes from our NCERT solutions and practising questions from our Important Questions Class 9 Science Chapter 15 will help students fully prepare for the subject.

A few of the benefits of solving questions from our Important Questions Class 9 Science Chapter 15 are:

  • Questions from all the chapter topics have been carefully taken as per the examination pattern and the latest CBSE syllabus. The step-by-step solutions are prepared by subject matter experts with years of experience to provide credible study material based on the NCERT textbooks which is complete in every way and students need not look elsewhere for any other resources.  Hence, students can rely on the Extramarks for any help and support.
  • The questions are selected and hand-picked from sources like NCERT textbooks, NCERT exemplar and other standard books for students to practice and excel. Solving questions from our Class 9 Science Chapter 15 Important Questions will help students to improve their knowledge and understanding of the concepts, time management, and confidence during the exams.
  • The solutions are provided in a step-by-step format so that students don’t miss out on any of the questions and lose marks due to minor mistakes. Solutions are complete in every way and students need not look elsewhere for any other resources.  Hence, students can rely on important questions and trust these solutions completely.
  • All the solutions are re-checked by the subject experts, ensuring students  reliable and accurate study material. In fact, these resources are the best study material for getting a 100% score and creating your first milestone in high school. 

Extramarks believes in incorporating joyful learning experiences through its own repository of resources. Students can find other study materials on our website. Click on the below links to get access to these resources:

Q.1 The composition of two atomic particles is given below:        

           A             B
Protons 6 6
Electrons 6 6
Neutrons 6 8

(a) What is the mass number of A and B?
(b) Which element/elements do they represent?
(c) What is the relation between A and B?  


(a) Mass number of A = 6 + 6 =12

Mass number of B = 6 + 8 =14

(b) Since number of protons in both A and B are 6. So, Both A and B represent Carbon atom.

(c) A and B have same number of protons/electrons, but they have different number of neutrons. Therefore, they are isotopes.

Q.2 Describe how electrons in an atom are arranged in different shells.


The arrangement of electrons in the various shells of an atom of the element is known as electronic configuration of the element. According to Bohr and Burry,

(a) The maximum number of electrons which can be accommodated in any energy level of the atom is given by 2n2 where n = 1, 2, 3, …(energy level).

Electronic Shell Maximum Capacity
1. K shell 2 electrons
2. L shell 8 electrons
3. M shell 18 electrons
4. N shell 32 electrons

(b) The outermost shell do not contain more than 8 electrons even if they have the capacity to accommodate more electrons.

(c) Electrons are not accommodated in a given shell, unless the inner shells are filled, i.e., shells are filled in a step-wise manner.

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FAQs (Frequently Asked Questions)

1. How can you improve my understanding of science and be strong in the subject?

 One can make Science strong by following these steps: 

  • Read the entire chapter from the NCERT textbook thoroughly.If it is difficult, divide into sections and take notes as soon as you complete one section. Complete the rest similarly.
  • Practice questions related to it.
  • Revise all the topics given in the syllabus from time to time.
  • Practice all the problems and solutions in the in-text, do the end-text exercises and browse through the summary. Study regularly without fail.
  • Attempt mock tests to get a good command of the various topics and get an excellent score. 

2. What is the interesting topic in Science Class 9 Chapter 15 ?

The most interesting topic is genetically modified crops. The process and technology involved may generate curiosity among the students while learning the topic

3. What are the breeds of cows?

 Draught breeds, dairy breeds and dual-purpose breeds. 

4. How does moisture affect grain storage?

When the moisture content is more than 14 % the microbes attack the grain.

5. What type of question patterns are covered in Important Questions Class 9 Science Chapter 15?

 The various patterns covered are as follows:

  • Long question and answers
  • Short type questions and answers
  • Fill in the blanks
  • Multiple choice questions
  • Match tables 

6. What are the topics covered in Class 9 Science Chapter 15?

 Below topics are covered in Chapter 15 of Class 9 Science:

  • Crops
  • Improvement in crop yields.
  • Manures.
  • Fertilizers
  • Irrigation
  • Cropping patterns
  • Crop protection Management
  • Types of insects that attack plants.
  • Weed control
  • Storage of grains
  • Animal husbandry.
  • Poultry farming
  • Fish Production
  • Prevention and control of animal and poultry diseases.