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CBSE Questions for Class 8 Biology Microorganisms Friend And Foe Quiz 3 - MCQExams.com

________ is used to make wine and bread.
  • Amoeba
  • Yeast
  • Both A and B
  • Bread mould
A communicable disease is generally caused by
  • Metabolic disorder
  • Hormonal imbalance
  • Allergy
  • Pathogen
Alcohol is produced during the process of:
  • Aerobic respiration
  • Combustion
  • Fermentation
  • Krebs cycle
Oil and vinegar are used for the preservation of:
  • Vegetables
  • Fish
  • Meat
  • All of the above
Cholera 
  • Is a non-communicable disease
  • Spreads through food and water
  • Spreads through air
  • Spreads through mosquitoes
Why oil and vinegar is used as preservative?
  • Because viruses can't live in such environment
  • It inhibits the growth of algae
  • Both a and b
  • Inhibits the growth of bacteria
Droplet infection is a type of
  • Direct transmission
  • Indirect transmission
  • Vector transmission
  • All of the above
Which of the following diseases is not caused by bacteria?
  • Typhoid
  • Anthrax
  • Malaria
  • Tuberculosis
Mark the incorrect statement   
  •  Microbes help in cleaning the environment
  • Microbes used to deposit the smelly and harmful substance
  • Both A and B
  • None of these
In the rainy season, moist bread gets spoilt and its surface gets covered with greyish-white patches. It is due to 
  • Micro-organisms
  • Herbivores
  • Rusts
  • None
Mark the correct statement
a) Microbes can only survive in cold climates
b) Microbes are found inside the bodies of animals
c) Microbes can grow on other organisms
  • a, b, c
  • a, b
  • a, c
  • b, c
Microbes are classified into ______ major groups.
  • 4
  • 3
  • 2
  • 1
Pasteurized milk can be consumed without boiling because: 
  • It is free from enzymes
  • It is free from microbes
  • It is free from preservatives
  • Both A and B
Mark the correct statement.
  • Microbes are only harmful to our body.
  • Microbes are only useful to our body.
  • Microbes can be both useful and harmful to our body.
  • Microbes can neither be useful nor harmful to our body.
Mark the correct statement  
  • Microbes spoil leather
  • Microbes spoil clothing
  • Microbes spoil food
  • All of theses
When a plant or animal dies it 
  • Leaves behind nutrients
  • Leaves behind energy
  • Leaves behind nothing
  •  Both A and B
Disease-causing microbes are called:
  • Gut flora 
  • Pathogens
  • Microorganisms
  • Fungi 
Micro-organisms include 
(a) Bacteria (b) Viruses (c) Protozoa (d) Algae
  • a, b, c, d
  • a, b
  • b, c
  • a, c
Which of the following is not a measure for prevention of typhoid
  • Clean drinking water
  • Proper sanitation
  • Better hand washing
  • None of these
Typhoid is not caused by _________
  • Eating or drinking contaminated food and water
  • Eating fast foods
  • Poor sanitation
  • All of the above
Cholera can be prevented by

a) Proper sanitation
b) Sterilisation techniques
c) Water treatment
d) Sewage treatment
  • b, c, d
  • a, b, c
  • c, d
  • All of the above
Why yeast is used in baking industry?
  • It reproduces rapidly.
  • Yeast produces carbon dioxide during respiration.
  • Both A and B
  • Because it is easily available in market.
Typhoid is caused by ________
  • Bacteria
  • Protozoa
  • Fungi
  • Virus
What is the main function of vaccine ?
  • Kill the microbes
  • Destroy the affected organ
  • Suppress the microbes
  • Stimulate the body's immune system
Typhoid can spreads through ________
  • Air
  • Water
  • Soil
  • Animals
What is the basis of using yeast is baking industry? 
  • Bubbles of gas fill the dough
  • Bubbles of gas increase its volume
  • Both A and B
  • None of these
Disease occurring due to airborne transmission is:
  • Tuberculosis
  • Chicken pox
  • Both A and B
  • Small pox
Why do we use salt in the preservation of fish and meat?
  • Salt checks the growth of algae
  • It makes the pickle tasty
  • It checks the growth of bacteria
  • Both A and C
Common preservative used in jam and pickles is ________
  • Sodium benzoate
  • Nitric acid
  • Sodium chloride
  • Copper sulphate
Chicken pox is a ______ borne disease.
  • Air
  • Water
  • Soil
  • Animal 
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