ROUTERA


Chapter 9 Strategies for Enhancement in Food Production

Class 12th Biology Chapter Assertion and Reason


1.

Assertion (A): The process of crossbreeding is used to develop new varieties of crops.
Reason (R): Crossbreeding helps combine desirable traits from two different varieties, leading to enhanced yield and disease resistance.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Crossbreeding combines the beneficial traits of two parent varieties, improving attributes like yield, disease resistance, and adaptability.


2.

Assertion (A): Genetic modification can enhance the nutritional content of crops.
Reason (R): Genetic modification involves the transfer of genes to introduce specific traits, such as increased vitamin content.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Genetic modification (GM) allows for the introduction of genes that can increase the nutritional value of crops, such as enhancing vitamin A content in rice (Golden Rice).


3.

Assertion (A): Hybrid varieties of crops are more productive than pure-bred varieties.
Reason (R): Hybrid varieties exhibit hybrid vigor, showing enhanced growth and yield due to the combination of genetic diversity.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Hybrids show hybrid vigor (heterosis), where the offspring are more robust and produce better yields than their parent varieties.


4.

Assertion (A): Plant breeding plays a crucial role in improving food production.
Reason (R): Plant breeding involves selecting desirable traits and combining them to improve crop yields and quality.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Plant breeding helps in the development of crops with better yield, disease resistance, and improved quality by selecting and combining desirable traits.


5.

Assertion (A): The use of biofertilizers enhances soil fertility.
Reason (R): Biofertilizers are natural fertilizers that improve nutrient availability by fixing nitrogen or decomposing organic matter.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Biofertilizers contain microorganisms that naturally enrich the soil with nutrients, such as nitrogen fixation and organic matter decomposition, thus improving soil fertility.


6.

Assertion (A): Bt-cotton is resistant to bollworm.
Reason (R): The genes responsible for producing Bacillus thuringiensis toxin are inserted into the cotton plant’s genome.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Bt-cotton has been genetically modified to produce a toxin from Bacillus thuringiensis, which is toxic to bollworms, thus making the plant resistant to pest damage.


7.

Assertion (A): Vermicomposting is an effective method of waste management.
Reason (R): Earthworms break down organic waste into nutrient-rich humus, improving soil structure and fertility.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Vermicomposting uses earthworms to decompose organic waste, converting it into valuable humus that improves soil fertility and structure.


8.

Assertion (A): Aquaculture is an important method for enhancing food production.
Reason (R): Aquaculture allows the cultivation of fish and other aquatic organisms in controlled environments, leading to increased production.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Aquaculture involves farming fish and other aquatic species under controlled conditions, thus boosting food production and reducing pressure on wild fish populations.


9.

Assertion (A): Mycorrhizal fungi form a symbiotic relationship with plants.
Reason (R): Mycorrhizal fungi help plants absorb water and nutrients, particularly phosphorus, in exchange for sugars from the plant.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Mycorrhizal fungi form mutualistic relationships with plant roots, aiding in nutrient and water absorption while receiving carbohydrates from the plant.


10.

Assertion (A): Microorganisms can be used in food production.
Reason (R): Certain microorganisms are involved in processes like fermentation, which enhances the flavor and preservation of food.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Microorganisms like yeast and bacteria are used in fermentation to produce products like bread, yogurt, and alcohol, enhancing flavor and shelf life.


11.

Assertion (A): Fish is a rich source of proteins and essential fatty acids.
Reason (R): Fish contains high-quality proteins and omega-3 fatty acids, which are beneficial for health.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Fish is an excellent source of proteins and omega-3 fatty acids, which are essential for maintaining heart health and overall well-being.


12.

Assertion (A): Tissue culture technology helps in the production of disease-free plants.
Reason (R): Tissue culture involves growing plants in controlled environments from a small piece of tissue, ensuring the absence of pathogens.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Tissue culture techniques allow the production of disease-free plants by growing them from explants in sterile conditions, minimizing the risk of pathogen contamination.


13.

Assertion (A): In-vitro fertilization is a technique used for improving crop yields.
Reason (R): In-vitro fertilization allows controlled fertilization and crossbreeding, leading to better genetic combinations in crops.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: In-vitro fertilization is used in plant breeding to control fertilization and create hybrid varieties with improved characteristics like higher yields.


14.

Assertion (A): Transgenic crops are genetically modified to resist pests.
Reason (R): Genetic engineering techniques are used to introduce genes that produce pest-resistant proteins in crops.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Transgenic crops are engineered to produce proteins (like Bt toxin) that make them resistant to specific pests, reducing the need for chemical pesticides.


15.

Assertion (A): Agroforestry is the practice of integrating trees with crops or livestock.
Reason (R): Agroforestry helps increase biodiversity and provides economic benefits by combining the strengths of both trees and crops.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Agroforestry combines trees with crops or livestock, providing multiple benefits such as improved biodiversity, enhanced soil fertility, and economic returns from diverse sources.


16.

Assertion (A): Organic farming avoids the use of synthetic chemicals and fertilizers.
Reason (R): Organic farming promotes sustainable agriculture by using natural fertilizers and pesticides.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Organic farming uses natural or organic inputs instead of synthetic chemicals, emphasizing sustainability and environmental health.


17.

Assertion (A): Green Revolution led to an increase in food production.
Reason (R): The Green Revolution introduced high-yielding varieties of crops, chemical fertilizers, and modern farming techniques.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: The Green Revolution transformed agriculture by introducing high-yielding varieties, chemical fertilizers, and advanced irrigation techniques, leading to increased food production.


18.

Assertion (A): The use of biopesticides reduces the environmental impact of farming.
Reason (R): Biopesticides are derived from natural organisms and have a lower toxicity to non-target species compared to synthetic chemicals.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Biopesticides, being naturally derived, are less harmful to the environment and beneficial organisms, making them a more sustainable alternative to chemical pesticides.


19.

Assertion (A): Integrated pest management (IPM) combines biological, chemical, and cultural control methods.
Reason (R): IPM reduces pest populations to manageable levels without relying solely on chemical pesticides.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: IPM integrates multiple pest control strategies to minimize the use of chemical pesticides and reduce their environmental impact while effectively controlling pests.


20.

Assertion (A): Biofortification involves enhancing the nutritional quality of crops.
Reason (R): Biofortification increases the content of essential vitamins and minerals in crops through breeding or genetic modification.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Biofortification aims to improve the nutritional content of crops, such as increasing the levels of Vitamin A, iron, or zinc, to combat malnutrition.


21.

Assertion (A): Monoculture farming can deplete soil nutrients.
Reason (R): Growing the same crop repeatedly in the same soil leads to the depletion of specific nutrients that the crop requires.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Monoculture farming, when practiced over extended periods, depletes the soil of specific nutrients, requiring the use of synthetic fertilizers to replenish them.


22.

Assertion (A): Crossbreeding improves the disease resistance of plants.
Reason (R): Crossbreeding combines desirable traits from different plant varieties, including resistance to specific diseases.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: By combining the genetic material from different varieties, crossbreeding can enhance disease resistance in plants.


23.

Assertion (A): Pesticides can be harmful to the environment.
Reason (R): Pesticides can affect non-target organisms like pollinators and soil microorganisms, disrupting the ecosystem.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: The widespread use of pesticides can have unintended consequences on the environment by harming beneficial organisms, such as bees and soil microorganisms, thus disturbing the ecosystem balance.


24.

Assertion (A): Irrigation plays a significant role in crop production.
Reason (R): Irrigation provides a consistent water supply, helping crops grow in regions with inadequate rainfall.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Irrigation is essential for maintaining adequate soil moisture for crops, especially in arid regions or during dry periods, ensuring consistent crop growth.


25.

Assertion (A): Crop rotation helps in maintaining soil fertility.
Reason (R): Different crops require different nutrients, and rotating crops allows the soil to replenish nutrients naturally.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Crop rotation prevents nutrient depletion and minimizes pest buildup by alternating crops with different nutrient requirements, which helps maintain soil fertility.

26.

Assertion (A): The use of genetically modified (GM) crops can reduce the need for chemical pesticides.
Reason (R): GM crops can be engineered to resist specific pests, reducing the reliance on chemical pesticides.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: GM crops can be engineered to produce their own pest-resistant proteins (e.g., Bt toxin), reducing the need for chemical pesticides and minimizing their environmental impact.


27.

Assertion (A): Organic farming promotes biodiversity.
Reason (R): Organic farming practices avoid the use of synthetic chemicals, which helps maintain a diverse range of organisms in the ecosystem.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: By avoiding synthetic pesticides and fertilizers, organic farming supports a healthier environment and promotes biodiversity, including beneficial insects and microorganisms.


28.

Assertion (A): The introduction of high-yielding varieties (HYVs) during the Green Revolution improved food security.
Reason (R): HYVs are more responsive to fertilizers and irrigation, which increases their productivity and helps feed larger populations.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: High-yielding varieties (HYVs) were designed to produce more food per unit of land, and their responsiveness to fertilizers and irrigation contributed to increased food production during the Green Revolution.


29.

Assertion (A): Animal husbandry is an important part of enhancing food production.
Reason (R): Animal husbandry involves breeding animals for food, fiber, and other products, contributing to food security and agricultural income.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Animal husbandry contributes to food production by providing meat, milk, wool, and other products, improving food security and the economy.


30.

Assertion (A): Synthetic fertilizers can lead to soil degradation.
Reason (R): Overuse of synthetic fertilizers can lead to soil acidification and a decrease in soil microbial diversity.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Excessive use of synthetic fertilizers can disrupt the natural balance of the soil, leading to reduced microbial diversity and soil acidification, which harms long-term soil fertility.


31.

Assertion (A): Biofortification increases the mineral content of crops.
Reason (R): Biofortification uses breeding techniques or genetic engineering to increase essential nutrients like iron, zinc, and calcium in crops.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Biofortification aims to improve the nutritional content of crops, helping to combat malnutrition by increasing the levels of vitamins and minerals in staple foods.


32.

Assertion (A): Vermicomposting is an eco-friendly method of waste management.
Reason (R): Earthworms decompose organic waste, turning it into nutrient-rich compost that enhances soil fertility.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Vermicomposting uses earthworms to process organic waste into high-quality compost, which is beneficial for soil health and an environmentally friendly alternative to chemical fertilizers.


33.

Assertion (A): Greenhouses are used to regulate the growth environment of crops.
Reason (R): Greenhouses provide controlled temperature, humidity, and light conditions, promoting faster and healthier plant growth.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Greenhouses help control the growing conditions of plants, making it possible to grow crops in regions with adverse climates, leading to improved yields and quality.


34.

Assertion (A): Hybrid varieties of crops have better resistance to diseases compared to non-hybrid varieties.
Reason (R): Hybrids combine traits from both parent plants, including resistance to specific diseases, resulting in stronger crops.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Hybrid crops exhibit increased disease resistance due to the genetic diversity inherited from both parent plants, leading to improved crop resilience.


35.

Assertion (A): The use of biopesticides reduces the risk of pesticide resistance in pests.
Reason (R): Biopesticides are natural or bio-based agents that target specific pests without affecting beneficial organisms.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Biopesticides are specific to the target pests, reducing the chances of resistance development and minimizing harm to non-target organisms, such as pollinators and beneficial insects.


36.

Assertion (A): Tissue culture technology helps in the rapid multiplication of superior plants.
Reason (R): Tissue culture allows the propagation of genetically identical plants from small tissue samples, ensuring uniformity and high quality.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Tissue culture enables the rapid propagation of superior, disease-free plants from small tissue samples, ensuring consistency in plant quality and yield.


37.

Assertion (A): Plant tissue culture is used to produce disease-free plants.
Reason (R): In tissue culture, plants are grown in sterile conditions, preventing the spread of pathogens.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: By using sterile conditions during tissue culture, plants are less likely to carry diseases, and healthy, disease-free plants can be produced.


38.

Assertion (A): Micropropagation is a technique used to increase the number of plants.
Reason (R): Micropropagation uses tissue culture to produce a large number of genetically identical plants in a short time.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Micropropagation allows for the mass production of identical plants by growing them from small tissue samples, which is efficient for commercial plant production.


39.

Assertion (A): Crops grown through hydroponics require less water compared to traditional farming.
Reason (R): Hydroponics uses a nutrient-rich water solution to grow plants, reducing the need for large quantities of soil and water.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Hydroponic farming uses water more efficiently as it recycles the nutrient solution, leading to reduced water consumption compared to traditional soil-based farming.


40.

Assertion (A): The Green Revolution led to a significant increase in the use of fertilizers and pesticides.
Reason (R): High-yielding varieties (HYVs) required high inputs of fertilizers and pesticides to achieve maximum productivity.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: The Green Revolution's focus on increasing crop yields through HYVs was accompanied by an increased reliance on chemical fertilizers and pesticides to optimize growth.


41.

Assertion (A): Cry proteins produced by Bacillus thuringiensis are used to protect crops from pests.
Reason (R): Cry proteins are toxic to specific insects and prevent damage to crops.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Cry proteins produced by Bacillus thuringiensis are toxic to certain pests, providing an effective biological control method for crop protection.


42.

Assertion (A): Manure is a natural fertilizer used in organic farming.
Reason (R): Manure is derived from animal waste and provides essential nutrients to crops.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Manure is a natural fertilizer that enriches soil by providing essential nutrients like nitrogen, phosphorus, and potassium, which are necessary for plant growth.


43.

Assertion (A): The use of irrigation systems has revolutionized food production.
Reason (R): Irrigation systems ensure a consistent water supply, reducing dependency on seasonal rainfall.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Irrigation systems have transformed agriculture by providing a stable and controlled water supply, enabling farmers to grow crops even in areas with insufficient rainfall.


44.

Assertion (A): Cross-pollination increases genetic diversity in plants.
Reason (R): Cross-pollination involves the transfer of pollen between different plants, leading to the mixing of genetic material.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Cross-pollination increases genetic diversity by allowing the exchange of genetic material between different plant individuals, resulting in more varied offspring.


45.

Assertion (A): Tissue culture technology is often used to propagate rare and endangered plant species.
Reason (R): Tissue culture allows the growth of plants from small tissue samples, making it easier to propagate rare species without the need for large quantities of the original plant.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Tissue culture can be used to propagate endangered species by taking small tissue samples from a single plant, reducing the need for extensive wild collection.


46.

Assertion (A): Biotechnological methods have been used to improve the nutritional value of food crops.
Reason (R): Genetic modification and breeding techniques can increase the concentration of essential nutrients like vitamins and minerals in food crops.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Genetic modification and breeding programs aim to enhance the nutritional content of crops, helping to combat malnutrition, such as increasing vitamin A or iron levels in staple foods.


47.

Assertion (A): Agricultural biotechnology has the potential to reduce post-harvest losses.
Reason (R): Biotechnological techniques can develop crops with longer shelf life and resistance to pests, reducing losses after harvest.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Crops modified through biotechnology can have enhanced shelf life, resistance to spoilage, and fewer losses during storage and transportation.


48.

Assertion (A): Insect-resistant crops reduce the need for chemical pesticides.
Reason (R): These crops are genetically engineered to produce proteins that are toxic to specific insect pests, reducing the need for external chemical inputs.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Insect-resistant genetically modified crops, such as Bt cotton, produce their own pest-repelling proteins, reducing the need for chemical pesticides.


49.

Assertion (A): Agroforestry integrates trees with crops or livestock.
Reason (R): Agroforestry systems combine the benefits of trees with agricultural production, improving biodiversity, soil fertility, and overall sustainability.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Agroforestry combines trees with crops or livestock to improve land use efficiency, enhance soil health, and promote biodiversity, contributing to sustainable agriculture.


50.

Assertion (A): Integrated pest management (IPM) reduces the reliance on chemical pesticides.
Reason (R): IPM combines biological, cultural, and mechanical methods of pest control to reduce pest populations and minimize pesticide use.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Integrated pest management (IPM) incorporates various non-chemical pest control methods, thereby reducing the dependency on chemical pesticides and promoting sustainable farming practices.