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The World of Microbes

Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.

Classification of Microorganisms

Subtopic

Classification of Microorganisms under The World of Microbes for Grade 8 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Which of the following is an example of a protozoan?

    A.

    ChlamydomonasChlamydomonas

    B.

    AmoebaAmoeba

    C.

    SpirogyraSpirogyra

    D.

    PenicilliumPenicillium

  2. 2.

    To which group does the organism E.coliE. coli belong?

    A.

    Bacteria

    B.

    Fungi

    C.

    Protozoa

    D.

    Algae

  3. 3.

    Which microbe is known as the 'social' microbe because it often grows in large clusters or colonies?

    A.

    AmoebaAmoeba

    B.

    BacteriaBacteria

    C.

    ParameciumParamecium

    D.

    None of these

Download the worksheet for The World of Microbes - Classification of Microorganisms to practice offline. It includes additional chapter-level practice questions.

Friendly Microorganisms in Food and Industry

Subtopic

Friendly Microorganisms in Food and Industry under The World of Microbes for Grade 8 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Which of the following is used in the commercial production of citric acid for soft drinks?

    A.

    LactobacillusLactobacillus

    B.

    AspergillusAspergillus nigerniger

    C.

    RhizobiumRhizobium

    D.

    AmoebaAmoeba

  2. 2.

    During the preparation of bread, why does the dough become porous?

    A.

    Due to the evaporation of water

    B.

    Due to the escape of Carbon dioxide bubbles

    C.

    Due to the addition of salt

    D.

    Due to the presence of flour

  3. 3.

    In the nitrogen cycle, which organisms convert nitrogenous waste into nitrogen compounds in the soil?

    A.

    Insects

    B.

    Bacteria and fungi

    C.

    Birds

    D.

    Fish

Download the worksheet for The World of Microbes - Friendly Microorganisms in Food and Industry to practice offline. It includes additional chapter-level practice questions.

Medicinal Use of Microorganisms and Vaccines

Subtopic

Medicinal Use of Microorganisms and Vaccines under The World of Microbes for Grade 8 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Which of these is NOT a common antibiotic?

    A.

    Streptomycin

    B.

    Tetracycline

    C.

    Erythromycin

    D.

    Calcium Carbonate

  2. 2.

    Antibiotics are primarily used to treat which type of infection?

    A.

    Bacterial

    B.

    Viral

    C.

    Nutritional

    D.

    Mental

  3. 3.

    Which of these is used for the large-scale production of medicines?

    A.

    Microbes

    B.

    Sand

    C.

    Plastic

    D.

    Paper

Download the worksheet for The World of Microbes - Medicinal Use of Microorganisms and Vaccines to practice offline. It includes additional chapter-level practice questions.

Harmful Microorganisms and Disease Causation

Subtopic

Harmful Microorganisms and Disease Causation under The World of Microbes for Grade 8 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Food poisoning is caused by eating food contaminated by:

    A.

    Vitamins

    B.

    Minerals

    C.

    Microorganisms

    D.

    Pure water

  2. 2.

    Which of the following is a way to stop the spread of Tuberculosis?

    A.

    Keeping the patient in isolation

    B.

    Drinking pond water

    C.

    Sharing towels with the patient

    D.

    Avoiding vaccination

  3. 3.

    Microbes that cause diseases in humans are also known as:

    A.

    Germs

    B.

    Pollutants

    C.

    Parasites

    D.

    Decomposers

Download the worksheet for The World of Microbes - Harmful Microorganisms and Disease Causation to practice offline. It includes additional chapter-level practice questions.

Food Preservation Techniques

Subtopic

Food Preservation Techniques under The World of Microbes for Grade 8 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Why is salt used in the preservation of raw amla?

    A.

    To make it sweet

    B.

    To check microbial growth

    C.

    To increase its moisture

    D.

    To change its color to red

  2. 2.

    Food spoilage can be identified by which of the following?

    A.

    Fresh aroma

    B.

    Bright colors

    C.

    Foul smell

    D.

    Crunchy texture

  3. 3.

    Which of these food items is preserved by adding a layer of oil on top?

    A.

    Juice

    B.

    Pickle

    C.

    Bread

    D.

    Dry fruits

Download the worksheet for The World of Microbes - Food Preservation Techniques to practice offline. It includes additional chapter-level practice questions.

Nitrogen Fixation and the Nitrogen Cycle

Subtopic

Nitrogen Fixation and the Nitrogen Cycle under The World of Microbes for Grade 8 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Which of these is a part of the nitrogen cycle?

    A.

    Fixation of nitrogen by microbes

    B.

    Melting of ice caps

    C.

    Erosion of soil by wind

    D.

    Burning of fossil fuels

  2. 2.

    Biological nitrogen fixation is carried out by:

    A.

    Humans

    B.

    Chemicals in factories

    C.

    Living organisms like bacteria

    D.

    Solar energy

  3. 3.

    What is the form of nitrogen found in the air?

    A.

    Liquid nitrogen

    B.

    Solid nitrogen

    C.

    Gaseous nitrogen

    D.

    Nitrate crystals

Download the worksheet for The World of Microbes - Nitrogen Fixation and the Nitrogen Cycle to practice offline. It includes additional chapter-level practice questions.

The World of Microbes - Class 8 Science (CBSE) | Krit.club