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Free download in PDF CBSE Class 12 Biology Multiple Choice Questions(MCQs) with Answers. Here Gkseries provide Biology Solve Questions and Answers for CBSE Class 12 Students.
61
Niche is defined as
[A]
a component of an ecosystem
[B]
an ecologically adapted zone of a species
[C]
the physical position and functional role of a species within the community
[D]
all plants and animals living at the bottom of a water body.
Answer: the physical position and functional role of a species within the community
62
Animals from colder climates generally have shorter limbs. This is called
[A]
Allen’s rule
[B]
Niche rule
[C]
Johnson’s rule
[D]
Arber’s rule
63
Cyanobacteria are used as biofertilisers because they
[A]
are photosynthetic
[B]
grow easily anywhere
[C]
have mucilage
[D]
fix atmospheric nitrogen
Answer: fix atmospheric nitrogen
64
Methanogens, growing anaerobically on cellulosic material, produce
[A]
methane, carbon dioxide, hydrogen.
[B]
methane and hydrogen
[C]
methane and carbon dioxide
[D]
methane gas
Answer: methane, carbon dioxide, hydrogen.
65
The residue left after methane production from cattle dung is
[A]
used as manure
[B]
used in civil construction.
[C]
burnt
[D]
burned in land fills
66
The vitamin whose content increases following the conversion of milk into curd by lactic acid bacteria is [NCERT Exemplar]
[A]
vitamin B12
[B]
vitamin E.
[C]
vitamin C
[D]
vitamin D
67
BOD of waste water is estimated by measuring the amount of [NCERT Exemplar]
[A]
oxygen evolution
[B]
oxygen consumption
[C]
total organic matter
[D]
biodegradable organic matter
Answer: oxygen consumption
68
Which one of the following is not a nitrogenfixing organism? [NCERT Exemplar]
[A]
Pseudomonas
[B]
Azotobacter
[C]
Anabaena
[D]
Nostoc
69
The primary treatment of waste water involves the removal of [NCERT Exemplar]
[A]
stable particles
[B]
harmful bacteria.
[C]
dissolved impurities
[D]
toxic substances
70
Propionibacterium produces large holes in swiss cheese due to the
[A]
formation of large amount of CO2
[B]
consumption of carbohydrates
[C]
process of oxidation of the dough
[D]
all of these
Answer: formation of large amount of CO2
71
Bacillus thuringiensis is used to control
[A]
insect pests
[B]
bacterial pathogens
[C]
fungal pathogens
[D]
nematodes
72
Lactic acid is formed by the process of
[A]
fermentation
[B]
glycolysis
[C]
citric acid cycle
[D]
P-oxidation
73
Which one of the following combination would a sugarcane farmer look for in the sugarcane crop?
[A]
Thick stem, long intemodes, high sugar content and disease resistant.
[B]
Thick stem, low sugar content, disease resistant.
[C]
Thick stem, high sugar content and profuse flowering.
[D]
Thick stem, short intemodes, high sugar content, disease resistant.
Answer: Thick stem, long intemodes, high sugar content and disease resistant.
74
The biggest constraint of plant breeding is
[A]
availability of desirable gene in the crop and its wild relatives.
[B]
infrastructure.
[C]
trained manpower.
[D]
transfer of genes from unrelated sources.
Answer: availability of desirable gene in the crop and its wild relatives.
75
Inbreeding is carried out in animal husbandry because it
[A]
increases heterozygosity.
[B]
increases homozygosity.
[C]
increases vigour.
[D]
improves the breed.
Answer: increases homozygosity.
76
Breeding of crops to increase the levels of essential nutrients, is called
[A]
biotechnology.
[B]
biofortification.
[C]
biomagnification.
[D]
bioinformatics.
Answer: biofortification.
77
The technique of obtaining a large number of plantlets by tissue culture method is known as
[A]
organ culture.
[B]
micropropagation.
[C]
plantlet culture.
[D]
macropropagation.
Answer: micropropagation.
78
Transplantation of tissues/organs to save certain patients often fails due to rejection of such tissues/organs by the patient. Which type of immune response is responsible for such rejections? [NCERT Exemplar]
[A]
auto-immune response
[B]
humoral immune response
[C]
physiological immune response
[D]
cell-mediated immune response
Answer: cell-mediated immune response
79
Many diseases can be diagnosed by observing the symptoms in the patient. Which group of symptoms are indicative of pneumonia? [NCERT Exemplar]
[A]
High fever, weakness, stomach pain, loss of appetite and constipation
[B]
Constipation, abdominal pain, cramps, blood clots
[C]
Difficulty in respiration, fever, chills, cough, headache
[D]
Nasal congestion and discharge, cough, sorethroat, headache
Answer: Difficulty in respiration, fever, chills, cough, headache
80
The substance produced by a cell on viral infection that can protect other cells from further infection is [NCERT Exemplar]
[A]
interferon
[B]
histamine
[C]
serotonin
[D]
colostrum
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