Class 9 Science Chapter 12 Previous Year Questions - Improvement in Food Resources

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Short Answer Type Questions

Q1. Explain intensive fish farming with the help of one example.  

 Ans: Intensive fish farming involves cultivating multiple fish species in a single pond, maximising space and resources. One effective method is the composite fish culture system, which includes five or six different species that have distinct feeding habits. This approach prevents competition for food.

• Catla: Feeds at the water surface.
• Rohu: Feeds in the middle zone.
• Mrigal and Common Carp: Bottom feeders.
• Grass Carp: Feeds on aquatic weeds.

By selecting species that occupy different feeding zones, the available food in the pond is fully utilised, leading to increased fish yield.

Q2. State one factor which affects the quality of honey produced. 

Ans: The quality of honey is influenced by the flowers available to bees. Key factors include:

• Nectar source: The type of flowers determines the nectar's quality.
• Pollen availability: Pollen contributes to the overall nutrition of the bees.
• Variety of flowers: A diverse range of flowers can enhance the honey's flavour.

 

Q3. Give two examples of shellfish.   

Ans: Shellfish are divided into two main groups:

• Crustaceans: Examples include crabs and lobsters.
• Molluscs: Examples include octopus and oysters.

Examples of Shellfish

Q4. Mention the names of four marine fish of high economic value. 

Ans: The four marine fish of high economic value are:

• Catla
• Rohu
• Common Carp
• Mrigal

Q5. (a) Define weed. Give two examples.
(b) Why is it essential to remove weeds from agricultural fields?
(c) What are weedicides?    

(a) Weeds are small-sized unwanted plants which grow along with a cultivated crop in the field, e.g. Xanthium, Parthenium etc.
(b) It is essential to remove the weeds from the agricultural field as they can severely reduce the crop yield by competing for light, water and nutrients.
(c) Weedicides are chemicals which are sprayed in the field to kill the weeds, e.g. atrazine. isoproturon etc.

Q6. In the summer vacation, the students of IX standard were given an investigatory project. They were asked to visit a dairy farm and note down their observations. Vinay took information from the internet and made the project while Sakshi visited the dairy, saw how and what cattle are fed with, how much milk they give per day. She also learned about the diseases they suffer from and how they are cleaned and taken care of.
(i) What kind of feed is given to cattle to increase milk production?
(ii) Write down two symptoms of a sick animal.
(iii) Why and whose characteristics would you like to adopt between Sakshi and Vinay?

(i) Concentrates which are low in fibre but contains high levels of proteins and other nutrients are required as feed for cattle to increase milk production.
(ii) Symptoms of sick animals are:

• They don't feed normally.
• They don't have normal posture.

(iii) I will like to adopt the characteristics of Sakshi. One cannot learn and experience the feeling of field trip simply by browsing the internet. Method adopted by Vinay if continued by him may affect the character of Vinay when he grows. One must be honest with his work as these practices give birth to a person of strong character.

Q7. Explain the ways by which crop production can be increased. 

Ans: Crop production can be increased by adopting suitable practices in farming and are divided into 3 major groups of activities:

• Crop variety improvement: This approach depends on the finding of a crop variety that can give a good yield. Varieties of crops can be selected by breeding for various useful characteristics such a disease resistance, response to fertilizer, product quality and high yield. One way of incorporating desired characters is hybridization. Another way of improving the crop is by introducing genes that would provide the desired character.
• Crop production improvement: It depends on the financial condition of the farmer. Crop production is of 3 types viz. low cost, high cost and no-cost production. Use of manures and fertilizers, mixed cropping, intercropping, crop rotation are some crop production practices available for crop production.
• Crop protection management: Crops in the field must be protected from weeds, pests and diseases. All these cause damages to the crop.
  Crop can be protected by:
  a) Use of pesticide
  b) Use of resistant varieties
  c) Crop rotation and other cropping systems
  d) Summer ploughing

Q8. Rahul and Rachna were practising floriculture on their farm. They sold the flowers to florists in India. They felt that if they start bee-keeping too, their income will increase. They obtained more information from the local officer.
(i) What is pasturage and how is it related to duality of honey?
(ii) Name a bee variety which is commonly used for commercial honey production.
(iii) Why society would appreciate Rahul and Rachna?   

(i) Pasturage is the flowers available to the bees for nectar and pollen collection. The taste and quality of honey depends on the kind of flowers available in the pasturage.
(ii) Apis cerana India commonly known as Indian bee is used for commercial honey production.
(iii) Rahul and Rachna have shown how to generate additional income without additional investment. This will be an eye-opener for the youth of the society.

Q9. Name the environmental factors related to cultivation practices and crops yield. Explain how they are related to crop yield.

Ans: Environmental factors related to cultivation practices and crop yield include various elements that influence the growth and productivity of crops. These factors are crucial for understanding how to optimise crop yield.

• Climatic conditions: Different crops require specific weather patterns, including temperature and rainfall, to thrive.
• Photoperiod: The duration of sunlight affects plant growth and flowering. Adequate sunlight is essential for photosynthesis, which is vital for food production in plants.
• Seasonality: Some crops are suited for the rainy season, while others flourish in winter. This seasonal adaptability impacts overall yield.
• Soil quality: The nutrient content and structure of the soil play a significant role in crop health and yield.
• Water availability: Sufficient water supply is critical, as drought or flooding can severely affect crop production.

Q10. India is a country with three fourth of the population engaged in agriculture. Even though the financial conditions of some farmers do allow them to take higher-level farming practices and improved agriculture technology, yet they are hesitant to use HYV seeds with traits such as resistance to diseases and pests, high quality that would finally result in higher yield. The Government’s Kisan channel solved all their apprehensions.
(i) What is meant by genetically modified crops?
(ii) What are the desired agronomic characters for fodder and cereal crops?
(iii) In your opinion, what should be done so that modern agriculture technology is adopted by most farmers? 

(i) Genetically modified crops are those plants in which the DNA have been modified using genetic engineering techniques.
(ii) For fodder-profuse branching, and for cereal-dwarfness
(iii) Modern agriculture technology will be adopted by the farmers, the farmers have a scientific temper, and they are made aware and given the knowledge to enhance agriculture practices.

Q11. Give one word for the following and give one example of each:
(a) Growing one row of crop alternately with the other crop.
(b) Growing two or more crops simultaneously in the same field.
(c) Growing of different crops on land in pre-planned succession.   

(a) Intercropping, e.g. soybean + Maize.
(b) Mixed cropping, e.g. wheat + gram.
(c) Crop rotation, e.g. potato, oats, peas and rye.

Long Answer Type Questions

Q1. (a) Name two common sources from which lists are captured.
(b) Why are mussels and shellfish cultivated?
(c) As the marine fish stock gets depleted, how tin demand for more fish can be met?
(d) How are marine fish caught?
(e) Name two marine fish of high economic value, which are also cultured in seawater   

(a) Following are two common sources from which fish are captured:

• Natural resources, e.g. sea, ocean, river, etc.
• By fish farming in freshwater and marine water,

(b) Mussels have high nutritive value. It is a good source of vitamins and has desirable fatty acids that improve brain function and also give important minerals like zinc that boosts immunity. Similarly, shellfish is also rich in vitamins, minerals, fish oil and it also brings in good revenue as seafood.
(c) The demand for more fish can be met with mariculture. Mariculture is the practice of cultivating only marine organisms for commercial purposes.
The advantages of mariculture are as follows:

• It is cultivated for food and products that give economical value and is important for industrial fishing:
• Farming of marine fish, prawn, shellfish are done in the open ocean or artificial ponds filled with seawater.

(d) Generally, fishes can be caught by hand gathering, netting, spearfishing, angling and trapping.
For commercial purposes, fishes from high seas are caught by long lines, gill nets, purse seines and bottom trawlers.
(e) The marine fishes that are cultivated in the sea and have high economic value are:

• Bhetki
• Mullets
• Pearl Spot.

Q2. (a) Distinguish between macronutrients and micronutrients on the basis of
(i) their functions
(ii) the amount required by plants.
(b) Classify the following elements as macro or micronutrients in plants
(i) Nitrogen
(ii) Zinc
(iii) Copper
(iv) Potassium
(c) In what way is deficiency of these nutrients harmful to crops? 

(a)

Macronutrient	Micronutrient
They are involved in forming carbon compounds in energy storage reactions(photosynthesis).	They are the minerals involved in enzymatic reactions.
Utilised by plants in large quantities.	Utilised by plants in small quantities.

(b)

• Nitrogen- Macronutrient
• Zinc- Micronutrient
• Copper- Micronutrient
• Potassium- Macronutrient

(c) Deficiency of nutrients affects physiological processes in plants including reproduction, growth and susceptibility to diseases.

Q3. Define genetically modified crops. How are they made? Explain the significance of genetically modified crops with suitable examples. 

Ans: Genetically modified crops are those plants in which the DNA have been modified using genetic engineering techniques. The aim of making a GM crop is to introduce a new trait into the plant which does not occur naturally in the species.
Technique: In GM crops, genes are added or removed using genetic engineering techniques. In this technique, DNA from another species of the same kingdom is bound to tiny particles of gold or tungsten which are subsequently shot into plant tissue under high pressure. The accelerated particles penetrate both, the cell wall and membranes. The DNA gets separated from the metal and is integrated into the plant DNA inside the nucleus.
Significance: GM crop has increased yield of the crop. Due to higher yield, it gives more income and has made the economic conditions of farmers cultivating GM crops better. While on one hand, farming land area is almost constant, and the human population is increasing every day. GM crop has made it possible to feed the growing population even though the farming land remains constant.