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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.
(16)
Secondary sewage treatment is mainly a
[1]
Biological process
[2]
Chemical process
[3]
Virtual process
[4]
Physical process
Answer: Biological process
(17)
During anaerobic digestion of organic waste, such as in producing biogas, which one of the following is left undergraded?
[1]
Hemi-cellulose
[2]
Lignin
[3]
Lipids
[4]
Cellulose
(18)
Which of the following is a symbiotic nitrogen fixer?
[1]
Azolla
[2]
Glomus
[3]
Azotobacter
[4]
Frankia
(19)
Ethanol is commercially produced through a particular species of
[1]
Aspergillus
[2]
Saccharomyces
[3]
Clostridium
[4]
Trichoderma
(20)
A patient brought to a hospital with myocardial infarction is normally immediately given
[1]
Cyclosporin–A
[2]
Statins
[3]
Penicillin
[4]
Streptokinase
21
The term antibiotic was coined by:
[1]
Howard Florey
[2]
John Tyndall
[3]
Selman Waksman
[4]
Gerhard Domagk
22
An important drug is obtained from the bark of
[1]
Withania
[2]
Cinchona
[3]
Papaver
[4]
Momordica
23
Select the correct statement from the following
[1]
Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria
[2]
Biogas is produced by the activity of aerobic bacteria on animal waste
[3]
Methanobacterium is an aerobic bacterium found in rumen of cattle
[4]
Biogas, commonly called gobar gas, is pure methane
Answer: Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria
24
Which of the following microbes is used for commercial production of ethanol?
[1]
Trichoderma polysporum
[2]
Streptococcus
[3]
Clostridium butylicum
[4]
Saccharomyces cerevisiae
Answer: Saccharomyces cerevisiae
25
Which of the following will begin fixing nitrogen only after they stop reproducing?
[1]
Penicillium
[2]
Rhizobium
[3]
Aspergillus
[4]
Streptococcus
26
Organisms called Methanogens are most abundant in a
[1]
Hot spring
[2]
Hot spring
[3]
Cattle yard
[4]
Polluted stream
27
Bacillus thuringiensis (Bt) strains have been used for designing novel
[1]
Biofertilizers
[2]
Bio-mineralization processes
[3]
Bio-insecticidal plants
[4]
Bio-metallurgical techniques
Answer: Bio-insecticidal plants
28
What is the common name of Drosophila melanogaster?
[1]
Fruit fly
[2]
Roundworm
[3]
Zebrafish
[4]
Chlamydia
29
The most abundant prokaryotes helpful to humans in making curd from milk and in production of antibiotics are the ones categorized as
[1]
Chemosynthetic autotrophs
[2]
Heterotrophic bacteria
[3]
Cyanobacteria
[4]
Archaebacteria
Answer: Heterotrophic bacteria
30
Which one of the following is not used in organic farming?
[1]
Glomus
[2]
Snail
[3]
Oscillatoria
[4]
Earthworm
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