Madmaths Quiz Science Quiz

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Madmaths Quiz Science Quiz - Quiz

Science quiz for class 8


Questions and Answers
  • 1. 

    Fabric is made of

    • A.

       steel

    • B.

      Fibre

    • C.

      Paper

    • D.

      None of these.

    Correct Answer
    B. Fibre
    Explanation
    Fabric is made of fibers, which are thin strands of materials that are woven or knitted together to create a textile material. These fibers can be natural, such as cotton or silk, or synthetic, such as polyester or nylon. By combining these fibers, fabrics with different properties and characteristics can be created, such as softness, durability, or moisture-wicking abilities. Therefore, the correct answer is "fibre."

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  • 2. 

     The small units used in making synthetic fibres are.

    • A.

      Molecules

    • B.

      Polymers

    • C.

      Cells

    • D.

       none of these.

    Correct Answer
    B. Polymers
    Explanation
    Polymers are the small units used in making synthetic fibers. A polymer is a large molecule made up of repeating subunits called monomers. In the case of synthetic fibers, these monomers are chemically bonded together to form long chains, which then intertwine to create the fibers. Therefore, polymers are the correct answer as they are the building blocks of synthetic fibers.

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  • 3. 

    The strongest fibre is called:

    • A.

      Rayon

    • B.

      Nylon

    • C.

      Acrylic

    • D.

      None of these.

    Correct Answer
    B. Nylon
    Explanation
    Nylon is the correct answer because it is known for its exceptional strength and durability, making it one of the strongest fibers available. It is commonly used in the production of various materials, including clothing, ropes, and industrial products. Rayon and acrylic, on the other hand, are not as strong as nylon and are used for different purposes. Therefore, nylon is considered the strongest fiber among the options given.

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  • 4. 

    The first man-made fibre is

    • A.

      Nylon

    • B.

      Polyester

    • C.

      Rayon

    • D.

      Cotton

    Correct Answer
    A. Nylon
    Explanation
    Nylon is considered the first man-made fiber because it was the first synthetic fiber created by humans. It was developed in the 1930s by a team of scientists at DuPont, led by Wallace Carothers. Nylon is known for its strength, durability, and resistance to abrasion, making it suitable for a wide range of applications such as clothing, upholstery, and industrial materials. Its invention revolutionized the textile industry and paved the way for the development of other synthetic fibers like polyester and rayon.

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  • 5. 

    The fibre made up by the chemical treatment of wood pulp is

    • A.

      Rayon

    • B.

      Nylon

    • C.

      Polyester

    • D.

      None of these.

    Correct Answer
    A. Rayon
    Explanation
    Rayon is the correct answer because it is a type of fiber that is made from the chemical treatment of wood pulp. It is a semi-synthetic fiber that is known for its softness, breathability, and ability to mimic the properties of natural fibers like cotton and silk. Rayon is widely used in the textile industry for making various types of clothing, including shirts, dresses, and lingerie. It is also used in the production of home furnishings and industrial products.

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  • 6. 

    The raw materials used in making nylon

    • A.

      Wood pulp

    • B.

      Cellulose

    • C.

      Coal, water, air

    • D.

      All of these

    Correct Answer
    C. Coal, water, air
    Explanation
    Nylon is a synthetic polymer that is made from coal, water, and air through a process called polymerization. Coal provides the carbon source, while water and air provide the necessary elements for the reaction. Wood pulp and cellulose are not used in the production of nylon. Therefore, the correct answer is coal, water, and air.

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  • 7. 

    What are some advantages of synthetic materials?

    • A.

      Cheaper to manufacture 

    • B.

      Stronger than similar products made from natural material

    • C.

      Often better quality 

    • D.

      All of the above

    Correct Answer
    D. All of the above
    Explanation
    Synthetic materials have several advantages. Firstly, they are cheaper to manufacture compared to natural materials, making them more affordable for consumers. Secondly, synthetic materials are often stronger than similar products made from natural materials, providing enhanced durability and longevity. Lastly, synthetic materials are frequently of better quality overall, offering improved performance and functionality. Therefore, the correct answer is "All of the above."

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  • 8. 

    It is not advisable to wear clothes made of synthetic fibre while working near fire because 

    • A.

      They are uncomfortable in those works

    • B.

      They melt on heating and cause heavy burns

    • C.

      They do not absorb moisture

    • D.

      They are shiny and lustrous.

    Correct Answer
    B. They melt on heating and cause heavy burns
    Explanation
    Synthetic fibers, such as polyester or nylon, have a low melting point. When exposed to heat or fire, these fibers can melt and stick to the skin, causing severe burns. This is why it is not advisable to wear clothes made of synthetic fibers while working near fire.

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  • 9. 

    Melamine is used for making

    • A.

      Kitchenware.

    • B.

      Floor tiles.

    • C.

      Fire-resistant fabrics.

    • D.

      All of them.

    Correct Answer
    D. All of them.
    Explanation
    Melamine is a versatile compound that is commonly used in the production of kitchenware, such as plates, bowls, and utensils, due to its durability, heat resistance, and ability to mimic the appearance of ceramic or porcelain. It is also used in the manufacture of floor tiles because of its resistance to moisture, stains, and wear. Additionally, melamine is utilized in the production of fire-resistant fabrics, as it has flame-retardant properties. Therefore, the correct answer is that melamine is used for making all of them: kitchenware, floor tiles, and fire-resistant fabrics.

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  • 10. 

    Which of the following material is a mixture of two fibres?

    • A.

      Jute

    • B.

      Polywool

    • C.

      Polyester

    • D.

      Nylon

    Correct Answer
    B. Polywool
    Explanation
    Polywool is a material that is made by blending or mixing two different fibers, namely polyester and wool. This combination results in a fabric that has the benefits of both fibers. Polyester is known for its durability, wrinkle resistance, and quick-drying properties, while wool provides warmth, softness, and moisture-wicking abilities. Hence, polywool is a mixture of these two fibers, making it the correct answer.

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  • 11. 

     Identify the synthetic fibre which resembles wool.

    • A.

      Rayon

    • B.

      Terylene

    • C.

      Nylon

    • D.

      Acrylic

    Correct Answer
    D. Acrylic
    Explanation
    Acrylic is the synthetic fiber that resembles wool. Acrylic fibers are soft, lightweight, and have a similar texture to wool. They are often used as a substitute for wool in clothing and textiles because they are less expensive and easier to care for. Acrylic fibers can be made to mimic the warmth and softness of wool, making them a popular choice for winter garments and blankets.

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  • 12. 

    Identify the type of plastic that can best be used to make electrical switches.

    • A.

      PVC

    • B.

      Polythene

    • C.

      PET

    • D.

      Bakelite

    Correct Answer
    D. Bakelite
    Explanation
    Bakelite is the best type of plastic to make electrical switches because it is a thermosetting plastic that has excellent electrical insulating properties, high heat resistance, and good mechanical strength. It can withstand high temperatures without melting or deforming, making it suitable for electrical applications. PVC, polythene, and PET are not as suitable for making electrical switches due to their lower heat resistance and insulating properties.

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  • 13. 

    Terylene is a popular form of

    • A.

      Polyester

    • B.

      Monomer

    • C.

      Plastic

    • D.

      Nylon

    Correct Answer
    A. Polyester
    Explanation
    Terylene is a popular form of polyester. Polyester is a synthetic polymer made from a combination of organic compounds called monomers. It is a type of plastic that is widely used in the textile industry due to its durability, wrinkle resistance, and ability to retain shape and color. Nylon, on the other hand, is a different type of synthetic polymer that is also used in textiles but has different properties compared to polyester.

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  • 14. 

    A. Cellulose is a polymer that is made up of a large number of small glucose molecules joined one after the other. b. Wood contains a very less amount of cellulose polymer. c. The small molecules that join together to form a polymer are called monomers.

    • A.

      Only a

    • B.

      Both a and b

    • C.

      Only b

    • D.

      Both b and c

    Correct Answer
    C. Only b
  • 15. 

    Synthetic fibres are synthesised from raw material called

    • A.

      Petrochemicals.

    • B.

       Wood pulp.

    • C.

      Plastics.

    • D.

       Plants.

    Correct Answer
    A. Petrochemicals.
    Explanation
    Synthetic fibers are man-made fibers that are created through a chemical process. Petrochemicals, which are derived from petroleum or natural gas, are the primary raw materials used in the synthesis of synthetic fibers. Wood pulp is used in the production of natural fibers such as cotton or rayon, but not synthetic fibers. Plastics can be used to create synthetic fibers, but they are not the raw material from which synthetic fibers are synthesized. Plants are not directly used in the synthesis of synthetic fibers.

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  • 16. 

    Which of the following is a rabi crop?

    • A.

      Mustard

    • B.

      Paddy

    • C.

      Maize

    • D.

      Soyabean

    Correct Answer
    A. Mustard
    Explanation
    Mustard is a rabi crop because it is sown in the winter season and harvested in the spring season. Rabi crops are crops that are grown during the winter months, typically from October to March, and require cool weather and less rainfall. Mustard is well-suited to these conditions and is commonly grown as a rabi crop in regions with a temperate climate. Paddy, maize, and soybean, on the other hand, are kharif crops that are sown in the rainy season and harvested in the autumn.

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  • 17. 

    Leguminous plants help in the replenishment of the soil with

    • A.

      Oxygen

    • B.

      Nitrogen

    • C.

      Hydrogen

    • D.

      Phosphorus

    Correct Answer
    B. Nitrogen
    Explanation
    Leguminous plants have a symbiotic relationship with nitrogen-fixing bacteria called rhizobia. These bacteria live in nodules on the roots of legumes and convert atmospheric nitrogen into a form that plants can use, called ammonium. This process is known as nitrogen fixation. As a result, leguminous plants are able to take in nitrogen from the air and incorporate it into their tissues. When these plants die or are harvested, the nitrogen-rich organic matter is returned to the soil, enriching it with nitrogen and benefiting other plants in the ecosystem. Therefore, leguminous plants help in the replenishment of the soil with nitrogen.

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  • 18. 

    Before sowing, seeds should be treated with

    • A.

      Insecticides

    • B.

      Pesticides

    • C.

      Fertilisers

    • D.

      Fungicides

    Correct Answer
    D. Fungicides
    Explanation
    Fungicides are used to treat seeds before sowing in order to protect them from fungal diseases. Insects, pests, and fertilizers are not directly related to preventing or treating fungal infections in seeds. Therefore, the correct answer is fungicides.

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  • 19. 

    Which of the following types of soil needs least frequent irrigation?

    • A.

      Sandy

    • B.

      Rocky

    • C.

      Loamy

    • D.

      Clayey

    Correct Answer
    D. Clayey
    Explanation
    Clayey soil needs the least frequent irrigation because it has a high water-holding capacity. The fine particles in clayey soil allow it to retain water for longer periods of time, reducing the need for frequent irrigation. In contrast, sandy soil has larger particles and drains water quickly, requiring more frequent irrigation. Rocky soil may have limited water-holding capacity due to the presence of rocks and may also drain water quickly. Loamy soil is a balanced mixture of sand, silt, and clay, and while it retains water better than sandy soil, it still requires more frequent irrigation compared to clayey soil.

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  • 20. 

    Chemicals that kill weeds are called

    • A.

      Fertilisers

    • B.

      Pesticides

    • C.

      Weedicides

    • D.

      Manures

    Correct Answer
    C. Weedicides
    Explanation
    Weedicides are chemicals specifically designed to kill weeds. Unlike fertilizers, which are used to provide nutrients to plants, weedicides target and eliminate unwanted weeds. Pesticides, on the other hand, are chemicals used to control or eliminate pests such as insects, while manures are organic materials used to improve soil fertility. Therefore, the correct answer for chemicals that kill weeds is weedicides.

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  • 21. 

    Which of the following is not a traditional method of irrigation?

    • A.

      Drip

    • B.

      Moat

    • C.

      Rahat

    • D.

      Chain pump

    Correct Answer
    A. Drip
    Explanation
    Drip irrigation is not a traditional method of irrigation. Traditional methods usually involve flooding or channeling water to the fields, whereas drip irrigation involves delivering water directly to the roots of plants through a network of pipes and emitters. This method is more efficient as it reduces water wastage and allows for precise control of water delivery.

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  • 22. 

    Which of the following statements is incorrect?

    • A.

      Loose soil particles have more air spaces

    • B.

      Loose soil particles hold less water for longer duration

    • C.

      Loose soil helps roots to penetrate deep through the layers of soil

    • D.

      Loose soil promotes the growth of useful soil microbes

    Correct Answer
    B. Loose soil particles hold less water for longer duration
    Explanation
    Loose soil particles actually have more air spaces, which allows for better water drainage and aeration. This means that loose soil can hold less water for a shorter duration, as the excess water drains away more easily.

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  • 23. 

    Which of the following is used for removing weeds and for loosening the soil?

    • A.

      Broadcasting

    • B.

      Traditional tool

    • C.

      Seed drill

    • D.

      Hoe

    Correct Answer
    D. Hoe
    Explanation
    A hoe is a gardening tool that is used for removing weeds and loosening the soil. It has a long handle with a sharp, flat blade at the end. By using a hoe, gardeners can easily cut through the soil and remove unwanted plants, such as weeds, without damaging the surrounding plants. Additionally, the action of hoeing also helps to break up compacted soil, allowing for better water and nutrient absorption by the plants. Therefore, a hoe is the correct tool for both weed removal and soil loosening.

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  • 24. 

    Rearing and large scale production of fish is called

    • A.

      Horticulture

    • B.

      Pisciculture

    • C.

      Animal husbandry

    • D.

      Apiculture

    Correct Answer
    B. Pisciculture
    Explanation
    Pisciculture refers to the rearing and large-scale production of fish. It involves the cultivation of fish in controlled environments such as fish farms or ponds. This practice is important for meeting the increasing demand for fish as a food source and for conservation purposes. Pisciculture involves various activities like breeding, hatching, feeding, and harvesting of fish. It plays a significant role in providing employment opportunities and contributes to the economy.

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  • 25. 

    Leaving the agricultural land uncultivated for one or more seasons is known as

    • A.

      Field fallow

    • B.

      Manuring

    • C.

      Crop rotation

    • D.

      Tilling

    Correct Answer
    A. Field fallow
    Explanation
    Field fallow refers to the practice of leaving agricultural land uncultivated for one or more seasons. This allows the land to rest and regenerate its nutrients, reducing the risk of soil erosion and improving its fertility. By not planting any crops, the land can recover and replenish its resources naturally. This practice is commonly used in sustainable farming methods to maintain the long-term health and productivity of the soil.

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  • 26. 

    Silo is used for

    • A.

      Large scale storage of food

    • B.

      Improvement of crop

    • C.

      Enhancing water holding capacity

    • D.

      Sowing of seeds

    Correct Answer
    A. Large scale storage of food
    Explanation
    A silo is a structure used for storing large quantities of food, such as grains or silage. It is designed to keep the stored food dry and protected from pests and spoilage. The other options mentioned, improvement of crop, enhancing water holding capacity, and sowing of seeds, are not directly related to the purpose of a silo. Therefore, the correct answer is large scale storage of food.

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  • 27. 

    Spyrogyra is

    • A.

      An algae

    • B.

      A fungi

    • C.

       A protozoa

    • D.

       A bacteria

    Correct Answer
    A. An algae
    Explanation
    Spyrogyra is classified as an algae because it is a filamentous green algae that is commonly found in freshwater environments. It has chloroplasts and carries out photosynthesis, which is a characteristic feature of algae. Spyrogyra is made up of long, thin filaments that form a spiral shape, giving it its distinctive appearance. It reproduces both sexually and asexually, and plays an important role in aquatic ecosystems as a primary producer. Overall, the characteristics and behavior of Spyrogyra align with those of algae, making it the correct answer.

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  • 28. 

    Vaccine for small pox is discorvered by

    • A.

       Louis Pasteur

    • B.

       Alexander Fleming

    • C.

       Edward Jenner

    • D.

      John Mendal

    Correct Answer
    C.  Edward Jenner
    Explanation
    Edward Jenner is credited with discovering the vaccine for smallpox. In the late 18th century, Jenner observed that milkmaids who had contracted cowpox, a less severe disease, seemed to be immune to smallpox. Based on this observation, he conducted an experiment where he inoculated a young boy with cowpox and later exposed him to smallpox, finding that the boy did not develop the disease. This led to the development of the smallpox vaccine, which was the first successful vaccine in history and ultimately led to the eradication of the disease.

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  • 29. 

      Scientist who discovered fermentation is

    • A.

       Alexander Fleming

    • B.

         Louis Pasteur

    • C.

      John Mendal

    • D.

      Edward Jenner

    Correct Answer
    B.    Louis Pasteur
    Explanation
    Louis Pasteur is credited with discovering fermentation. He conducted experiments in the 1850s that disproved the theory of spontaneous generation and instead showed that microorganisms were responsible for fermentation. Pasteur's work laid the foundation for the field of microbiology and revolutionized our understanding of fermentation processes, leading to advancements in industries such as brewing, winemaking, and food preservation.

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  • 30. 

    Which of the following is a disease caused by protozoans?

    • A.

      Tuberculosis

    • B.

      Polio

    • C.

      Malaria

    • D.

      Typhoid

    Correct Answer
    C. Malaria
    Explanation
    Malaria is a disease caused by protozoans. It is transmitted through the bite of infected female Anopheles mosquitoes. The protozoan parasite, Plasmodium, enters the bloodstream and infects the liver and red blood cells. This causes symptoms such as fever, chills, headache, and fatigue. If left untreated, malaria can be life-threatening. Effective prevention and treatment strategies include the use of insecticide-treated bed nets, antimalarial medications, and vector control measures.

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  • 31. 

    Which of the following diseases is caused by a bacteria?

    • A.

      Chicken pox

    • B.

      Tuberculosis

    • C.

      Dengue

    • D.

      Polio

    Correct Answer
    B. Tuberculosis
    Explanation
    Tuberculosis is caused by a bacteria called Mycobacterium tuberculosis. It is an infectious disease that primarily affects the lungs but can also affect other parts of the body. Chicken pox is caused by the varicella-zoster virus, Dengue is caused by the dengue virus, and Polio is caused by the poliovirus.

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  • 32. 

    In order to take precautionary steps to control dengue, we must take measures to stop the breeding of:

    • A.

      Aedes mosquito

    • B.

      Fleas

    • C.

      Fire ants

    • D.

      Anopheles mosquito

    Correct Answer
    A. Aedes mosquito
    Explanation
    To control dengue, it is important to stop the breeding of Aedes mosquitoes. Aedes mosquitoes are the primary carriers of the dengue virus and are responsible for transmitting it to humans. By preventing the breeding of Aedes mosquitoes, such as by eliminating stagnant water sources where they lay their eggs, we can reduce the population of these mosquitoes and decrease the risk of dengue transmission. Fleas, fire ants, and Anopheles mosquitoes are not directly associated with dengue transmission, so focusing on controlling Aedes mosquitoes is the most effective precautionary measure.

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  • 33. 

     Which of the following is a communicable disease?

    • A.

      Diabetes

    • B.

      Chicken pox

    • C.

      Alzheimer’s

    • D.

      Cancer

    Correct Answer
    B. Chicken pox
    Explanation
    Chicken pox is a communicable disease because it is caused by the varicella-zoster virus, which can be easily transmitted from person to person through direct contact or through respiratory droplets. It is highly contagious and can spread quickly in close quarters such as schools or households.

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  • 34. 

    While baking cakes, yeast reproduces rapidly and produces ___ gas.

    • A.

      Hydrogen

    • B.

      Oxygen

    • C.

      Carbon dioxide

    • D.

      Nitrogen

    Correct Answer
    C. Carbon dioxide
    Explanation
    During the process of baking cakes, yeast undergoes fermentation, which involves the breakdown of sugars to produce energy. As a byproduct of this process, carbon dioxide gas is released. The carbon dioxide gas gets trapped in the dough, causing it to rise and making the cake fluffy and light. Therefore, the correct answer is carbon dioxide.

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  • 35. 

    Which of the following diseases can be cured using antibiotics?

    • A.

      AIDS

    • B.

      Dengue

    • C.

      Typhoid

    • D.

      Malaria

    Correct Answer
    C. Typhoid
    Explanation
    Typhoid is the correct answer because it is a bacterial infection caused by the bacteria Salmonella typhi. Antibiotics are effective in treating bacterial infections by killing or inhibiting the growth of bacteria. AIDS, Dengue, and Malaria are caused by viruses, and antibiotics are not effective against viral infections.

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  • 36. 

    Which organisms are microscopic and dependent on host organisms for reproduction?

    • A.

      Algae

    • B.

      Protozoa

    • C.

      Viruses

    • D.

      Bacteria

    Correct Answer
    C. Viruses
    Explanation
    Viruses are microscopic organisms that are dependent on host organisms for their reproduction. Unlike other organisms such as algae, protozoa, and bacteria, viruses cannot reproduce on their own and must invade the cells of a host organism in order to replicate. They attach themselves to the host cell and inject their genetic material, taking control of the host's cellular machinery to produce more viruses. This dependence on a host organism for reproduction is a defining characteristic of viruses.

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  • 37. 

    Which one of the following is not a method of food preservation?

    • A.

      Salting

    • B.

      Drying

    • C.

      Pickling

    • D.

      Boiling

    Correct Answer
    D. Boiling
    Explanation
    Boiling is not a method of food preservation because it involves the application of heat to food, which can actually lead to the destruction of microorganisms and enzymes that cause food spoilage. While boiling can help kill certain bacteria and parasites in food, it is not a long-term preservation method as it does not prevent the growth of new microorganisms after the food cools down. In contrast, salting, drying, and pickling are all methods that can help preserve food by creating an environment that inhibits the growth of bacteria, fungi, and other microorganisms.

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  • 38. 

    Which one of the following is not produced by the process of fermentation?

    • A.

      Cheese

    • B.

      Milk

    • C.

      Yoghurt

    • D.

      Wine

    Correct Answer
    B. Milk
    Explanation
    Fermentation is a metabolic process that converts sugar into acids, gases, or alcohol. Milk is not produced by the process of fermentation. Instead, milk is produced by the mammary glands of mammals. Fermentation is commonly used to produce cheese, yogurt, and wine, but milk itself is not a product of this process.

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  • 39. 

    A plant disease called citrus canker is caused by a _________ .

    • A.

      Bacteria

    • B.

      Fungi

    • C.

      Protozoa

    • D.

      Virus

    Correct Answer
    A. Bacteria
    Explanation
    Citrus canker is a plant disease caused by bacteria. Bacteria are single-celled microorganisms that can infect plants and cause various diseases. In the case of citrus canker, the bacteria enter the plant through wounds or natural openings and multiply, leading to the formation of characteristic raised corky lesions on the leaves, stems, and fruit of citrus trees. These lesions can affect the growth and overall health of the plant, potentially leading to reduced fruit yield and quality. Therefore, the correct answer is bacteria.

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  • 40. 

    Which among the following pathogens causes cholera?

    • A.

      Protozoan

    • B.

      Bacteria

    • C.

      Fungus

    • D.

      Virus

    Correct Answer
    B. Bacteria
    Explanation
    Cholera is caused by bacteria. The bacterium responsible for causing cholera is called Vibrio cholerae. It is transmitted through contaminated water and food, and can cause severe diarrhea and dehydration. Treatment usually involves rehydration therapy and antibiotics. Protozoan, fungus, and virus are not known to cause cholera.

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  • 41. 

    Which of the following is a viral disease? 

    • A.

      Polio

    • B.

      Tuberculosis 

    • C.

      Typhoid

    • D.

      All of these

    Correct Answer
    A. Polio
    Explanation
    Polio is a viral disease caused by the poliovirus. It primarily affects the nervous system and can lead to paralysis or even death. It is transmitted through contaminated food, water, or contact with an infected person. There is no cure for polio, but vaccination can prevent its spread. Tuberculosis and typhoid, on the other hand, are bacterial diseases caused by Mycobacterium tuberculosis and Salmonella typhi respectively.

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  • 42. 

    Foot and mouth disease is a _____ disease.

    • A.

      bacterial

    • B.

      fungal

    • C.

      Protozoan

    • D.

      Viral

    Correct Answer
    C. Protozoan
    Explanation
    The given answer, protozoan, is incorrect. Foot and mouth disease is actually a viral disease.

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  • 43. 

    Conversion of nitrogen to ammonia is

    • A.

      nitrification

    • B.

      Phosphorylation

    • C.

      Denitrification

    • D.

      Nitrogen fixation

    Correct Answer
    D. Nitrogen fixation
    Explanation
    Nitrogen fixation is the process by which atmospheric nitrogen is converted into ammonia by certain bacteria. This process is essential for making nitrogen available to plants and other organisms, as atmospheric nitrogen is not directly usable. Nitrification refers to the conversion of ammonia to nitrate, phosphorylation is a process in which phosphate groups are added to molecules, and denitrification is the conversion of nitrate back to atmospheric nitrogen. Therefore, out of the given options, only nitrogen fixation is the correct process for the conversion of nitrogen to ammonia.

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  • 44. 

    Partial sterilization of a product such as milk at a high temperature is known as:

    • A.

      Pasteurization

    • B.

      Filtration

    • C.

      Pickling

    • D.

      Refrigeration

    Correct Answer
    A. Pasteurization
    Explanation
    Pasteurization is the process of heating a product, such as milk, to a high temperature for a short period of time in order to kill harmful bacteria and extend its shelf life. This method partially sterilizes the product, making it safer for consumption. Filtration involves passing a substance through a filter to remove impurities, while pickling refers to preserving food in a solution such as vinegar or brine. Refrigeration simply involves keeping a product at a low temperature to slow down bacterial growth. Therefore, the correct answer is pasteurization.

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  • 45. 

    Living organisms which are invisible to the naked eye are called _________ .

    • A.

      Particles

    • B.

      Molecules

    • C.

      Macroorganisms

    • D.

      Microorganisms

    Correct Answer
    D. Microorganisms
    Explanation
    Microorganisms are living organisms that are too small to be seen with the naked eye. They include bacteria, viruses, fungi, and protozoa. These organisms play a vital role in various ecosystems and have a significant impact on human health and the environment. They can be found in various habitats such as soil, water, and even inside the human body. Microorganisms are responsible for processes like decomposition, nutrient cycling, and fermentation. They can also cause diseases in plants, animals, and humans.

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