Class 9 Biology – Improvement in Food Resources
Exercises
Q1. Explain any one method of crop production which ensures high yield.
Plant Breeding
i. It is a method to improve crop varieties.
ii. Plants with desirable traits are selected.
iii. Selected plants are cross-bred (hybridisation).
iv. It produces high-yield and better quality crops.
Q2. Why are manure and fertilisers used in fields?
i. They increase soil fertility.
ii. They supply nutrients like nitrogen, phosphorus and potassium.
iii. They improve crop yield.
iv. They help in healthy plant growth.
Q3. What are the advantages of inter-cropping and crop rotation?
Inter-cropping
i. Reduces pest and disease spread.
ii. Prevents total crop failure.
iii. Reduces soil erosion.
iv. Uses water efficiently.
Crop Rotation
i. Allows growing more crops in a year.
ii. Improves soil fertility.
iii. Pulses add nitrogen to soil.
iv. Ensures proper use of nutrients.
Q4. What is genetic manipulation? How is it useful in agricultural practices?
i. Transfer of a specific gene to another organism.
ii. Produces genetically modified crops.
iii. Improves resistance to pests.
iv. Example: BT cotton.
v. Used in crops like brinjal, rice and maize.
Q5. How do storage grain losses occur?
Abiotic factors
i. Humidity
ii. Temperature
iii. Air
iv. Flood
v. Wind
Biotic factors
i. Insects
ii. Rodents
iii. Bacteria
iv. Mites
v. Birds
Q6. How do good animal husbandry practices benefit farmers?
i. Improves quality of animals.
ii. Increases milk production.
iii. Helps in farming activities.
iv. Improves farmer income.
Q7. What are the benefits of cattle farming?
i. Used for ploughing and transport.
ii. Produces milk and meat.
iii. Provides good quality breeds.
iv. Skin used for leather industry.
Q8. For increasing production, what is common in poultry, fisheries and bee-keeping?
i. Use of cross-breeding techniques.
ii. Proper care and maintenance.
iii. Disease control.
iv. Balanced feeding.
Q9. How do you differentiate between capture fishing, mariculture and aquaculture?
Capture Fishing
Mariculture
Aquaculture
i. Fish caught from natural water
i. Fish grown in sea water
i. Fish grown in fresh & marine water
ii. Rivers, lakes, seas
ii. Marine fish like prawns
ii. Ponds, rivers, seas
iii. No farming
iii. Marine farming
iii. Fish farming
Extra Questions
1. What do we get from cereals, pulses, fruits and vegetables?
i. Cereals give carbohydrates.
ii. Pulses give proteins.
iii. Fruits and vegetables give vitamins and minerals.
iv. Provide balanced nutrition.
2. How do biotic and abiotic factors affect crop production?
i. Biotic factors cause diseases.
ii. Pests and rodents reduce yield.
iii. Abiotic factors damage crops.
iv. Floods, drought and temperature affect growth.
3. What are the desirable agronomic characteristics for crop improvement?
i. Tallness and branching in fodder crops.
ii. Dwarfness in cereals.
iii. High yield.
iv. Disease resistance.
4. What are macro-nutrients, and why are they called macronutrients?
i. Needed by plants in large quantities.
ii. Essential for plant growth.
iii. Nitrogen, phosphorus and sulphur form proteins.
iv. Magnesium is part of chlorophyll.
Macronutrients (required in large amounts)
i. Carbon (C)
ii. Hydrogen (H)
iii. Oxygen (O)
iv. Nitrogen (N)
v. Phosphorus (P)
vi. Potassium (K)
vii. Calcium (Ca)
viii. Magnesium (Mg)
ix. Sulphur (S)
5. How do plants get nutrients?
i. Carbon and oxygen are obtained from air and water.
Example: Carbon from CO₂ is used in photosynthesis to make food.
ii. Remaining nutrients are obtained from the soil.
Example: Nitrogen, phosphorus and potassium are absorbed from soil.
iii. Nutrients are absorbed through roots (root hairs).
Example: Roots absorb nitrate and phosphate salts dissolved in water.
iv. Plants require 16 essential nutrients for growth.
Macronutrients (required in large amounts)
i. Carbon (C)
ii. Hydrogen (H)
iii. Oxygen (O)
iv. Nitrogen (N)
v. Phosphorus (P)
vi. Potassium (K)
vii. Calcium (Ca)
viii. Magnesium (Mg)
ix. Sulphur (S)
Micronutrients (required in small amounts)
i. Iron (Fe)
ii. Manganese (Mn)
iii. Zinc (Zn)
iv. Copper (Cu)
v. Boron (B)
vi. Molybdenum (Mo)
vii. Chlorine (Cl)
Total nutrients = 9 macronutrients + 7 micronutrients = 16 essential nutrients
6. Compare the use of manure and fertilisers in maintaining soil fertility.
Manure
Fertilisers
i. Adds humus
i. No humus
ii. Improves soil structure
ii. Makes soil hard
iii. Reduces erosion
iii. Increases erosion
iv. Eco-friendly
iv. Harmful if overused
7. Which of the following conditions will give the most benefits? Why?
(a) Farmers use high-quality seeds; do not adopt irrigation or use fertilisers.
(b) Farmers use ordinary seeds, adopt irrigation and use fertiliser.
(c) Farmers use quality seeds, adopt irrigation, use fertiliser and use crop protection measures.
Answer: (c)
because use of good quality seeds is not only sufficient until the soil is
properly irrigated, enriched with fertilisers and protected from biotic factors.
8. Why should preventive measures and biological control methods be preferred?
i. Chemicals cause pollution.
ii. Harm plants and animals.
iii. Bio-pesticides are safe.
iv. Eco-friendly method.
9. Which method is commonly used for improving cattle breeds and why?
i. Cross-breeding is used.
ii. Combines good qualities.
iii. Produces high-yield cattle.
iv. Improves climate resistance.
10. What management practices are common in dairy and poultry farming?
i. Clean and hygienic shelters.
ii. Nutritious food.
iii. Disease prevention.
iv. Proper ventilation and sunlight.
11. What are the differences between broilers and layers and their management?
Broilers
Layers
i. Raised for meat
i. Raised for eggs
ii. Protein-rich diet
ii. Balanced diet
iii. Less space
iii. More space
iv. Vitamins A & K needed
iv. Proper lighting needed
12. Discuss the implications of the following statement: “It is interesting to note that poultry is India’s most efficient converter of low-fibre foodstuff (which is unfit for human consumption) into highly nutritious animal protein food.”
i. Poultry converts low-fibre food.
ii. Produces nutritious meat and eggs.
iii. Efficient use of waste food.
iv. Provides rich animal protein.
13. How are fish obtained?
i. Capture fishing from natural waters.
ii. Culture fishery by farming.
iii. Freshwater and marine sources.
14. What are the advantages of composite fish culture?
i. Different fish use different food levels.
ii. No competition for food.
iii. Full use of pond resources.
iv. Higher yield.
Examples:
i. Catla – surface feeder
ii. Rohu – middle-zone feeder
iii. Mrigal – bottom feeder
iv. Common carp – bottom feeder15. What are the desirable characteristics of bee varieties for honey production?
i. High honey yield.
ii. Stay longer in hive.
iii. Less stinging nature.
iv. Disease resistant.
Examples of bee varieties:
i. Apis cerana indica – Indian bee
ii. Apis mellifera – Italian bee (high honey yield)
iii. Apis dorsata – Rock bee
iv. Apis florea – Little bee16. What is pasturage, and how is it related to honey production?
i. Availability of flowers for bees.
ii. Provides nectar and pollen.
iii. Determines honey quality.
iv. More flowers give better honey.