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Microbes in Human Welfare MCQs
Class XII Biology
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NCERT Based
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NEET Practice
📘 Concept Based
📝 Exam Level
🤖 AI Explanations
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455 questions in this chapter
Question 91 of 455
📘 CLASS XII
Which of the following diseases is NOT explicitly mentioned as being controlled or treated effectively due to the discovery of antibiotics?
The diseases mentioned are plague, whooping cough, diphtheria and leprosy.
Question 92 of 455
📘 CLASS XII
Which organic acid is produced commercially by the fungus *Aspergillus niger*?
Examples of acid producers are Aspergillus niger (a fungus) of citric acid.
Question 93 of 455
📘 CLASS XII
The collective term for the microbial masses (bacteria associated with fungal filaments) formed in the aeration tank is:
Vigorous growth of useful aerobic microbes into flocs (masses of bacteria associated with fungal filaments to form mesh like structures).
Question 94 of 455
📘 CLASS XII
Which process is necessary for producing highly pure alcoholic drinks like Brandy and Rum?
Whisky, brandy and rum are produced by distillation of the fermented broth.
Question 95 of 455
📘 CLASS XII
The major component of municipal waste-water (sewage) is:
A major component of this waste water is human excreta.
Question 96 of 455
📘 CLASS XII
Why can untreated sewage generally NOT be discharged directly into natural water bodies like rivers?
This cannot be discharged into natural water bodies like rivers and streams directly – before disposal, sewage is treated to make it less polluting.
Question 97 of 455
📘 CLASS XII
In primary sewage treatment, after sequential filtration removes floating debris, what is removed by sedimentation?
Initially, floating debris is removed by sequential filtration. Then the grit (soil and small pebbles) are removed by sedimentation.
Question 98 of 455
📘 CLASS XII
The volume of oxygen consumed if all organic matter in one liter of water were oxidized by bacteria is the definition of:
BOD refers to the amount of the oxygen that would be consumed if all the organic matter in one liter of water were oxidised by bacteria.
Question 99 of 455
📘 CLASS XII
During anaerobic digestion in the sludge digesters, the microbes primarily digest:
Other kinds of bacteria, which grow anaerobically, digest the bacteria and the fungi in the sludge.
Question 100 of 455
📘 CLASS XII
Which of these gases is produced by methanogens?
Methanogens produce large amount of methane along with CO2 and H2.
