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Free Download as PDF of the detailed solutions for class 12 Biology from NCERT or CBSE text book as per exam pattern, to help you in day to day learning. We provide all important questions and answers from chapter Microbes in Human Welfare of Biology.
(1)
Which of the followings is mainly produced by the activity of anaerobic bacteria on sewage?
[1]
Laughing gas
[2]
Propane
[3]
Marsh gas
[4]
Mustard gas
(2)
Pollution from animal excreta and organic waste from kitchen can be most profitably minimized by
[1]
Storing them in underground storage tanks
[2]
Using them for producing biogas.
[3]
Vermiculture
[4]
Using them directly as biofertilizers
Answer: Using them for producing biogas.
(3)
Which one of the following is used as biological insecticide?
[1]
Silkmoth
[2]
Caterpillar
[3]
Tiger beetle
[4]
Mazra Poka
(4)
Azolla is used as a biofertilizer because it
[1]
Has association of nitrogen fixing Cyanobacteria
[2]
Has association of nitrogen fixing Rhizobium
[3]
Multiplies very fast to produce massive biomass
[4]
Has association of mycorrhiza
Answer: Has association of nitrogen fixing Cyanobacteria
(5)
A nitrogen fixing microbe associated with Azolla in rice fields is
[1]
Frankia
[2]
Tolypothrix
[3]
Spirulina
[4]
Anabaena
(6)
Physical removal of large and small from the sewage through filtration and sedimentation is called:
[1]
Primary treatment
[2]
Secondary treatment
[3]
Tertiary treatment
[4]
Quaternary treatment
Answer: Primary treatment
(7)
The yeast that is used in alcohol production and bread making is
[1]
Escherichia coli
[2]
Saccharomyces cerevisiae
[3]
Bacillus subtilis
[4]
Pseudomonas putida
Answer: Saccharomyces cerevisiae
(8)
In paddy fields biological nitrogen fixation is chiefly brought by
[1]
Mycorrhiza
[2]
Green algae
[3]
Cyanobacteria
[4]
Rhizobium
(9)
Which of the following bacterium produces butyric acid?
[1]
Acetobacter aceti
[2]
Clostridium butylicum
[3]
Lactobacillus
[4]
None of these
Answer: Clostridium butylicum
(10)
Green manure plants used by farmer mainly belong to
[1]
Solanaceae
[2]
Compositae
[3]
Leguminosae
[4]
Poaceae
(11)
The common nitrogen-fixer in paddy fields is
[1]
Frankia
[2]
Rhizobium
[3]
Azospirillum
[4]
Oscillatoria
(12)
Human insulin is being commercially produced from a transgenic species of
[1]
Saccharomyces
[2]
Escherichia
[3]
Mycobacterium
[4]
Rhizobium
(13)
Morphine, which is used as an analgesic is obtained from
[1]
Taxus brevifolia
[2]
Papaver somniferum
[3]
Cinchona officinalis
[4]
Berberis nilghiriensis
Answer: Papaver somniferum
(14)
Which one of the following microbes forms symbiotic association with plants and helps them in their nutrition?
[1]
Glomus
[2]
Trichoderma
[3]
Azotobacter
[4]
Aspergillus
(15)
Yeast is used in the production of
[1]
Bread and beer
[2]
Cheese and butter
[3]
Citric acid and lactic acid
[4]
Lipase and pectinase
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