Class XII · Biology practice
Microbes in Human Welfare MCQs
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455 questions in this collection · Page 31 of 46
Question 301 of 455
📘 CLASS XII
Microbes In Human Welfare
In the human stomach, LAB (Lactic Acid Bacteria) play a beneficial role in checking _____.
In our stomach too, the LAB play very beneficial role in checking disease-causing microbes.
Question 302 of 455
📘 CLASS XII
Microbes In Human Welfare
The clarity of bottled fruit juices compared to homemade ones is due to the industrial use of pectinases and proteases to break down _____.
Pectinases and proteases break down Pectin and proteins to clarify juices.
Question 303 of 455
📘 CLASS XII
Microbes In Human Welfare
Untreated sewage cannot be discharged directly into natural water bodies because many of the microbes present in it are _____.
Sewage contains large amounts of microbes, many of which are pathogenic.
Question 304 of 455
📘 CLASS XII
Microbes In Human Welfare
BOD (Biochemical Oxygen Demand) measures the rate of uptake of _____ by micro-organisms in a sample of water.
The BOD test measures the rate of uptake of oxygen by micro-organisms in a sample of water.
Question 305 of 455
📘 CLASS XII
Microbes In Human Welfare
Assuming the river water is relatively clean, the sample labeled B with the lowest BOD (8mg/L) corresponds to _____.
BOD values: River water (clean) < Secondary effluent < Untreated sewage. B (8mg/L) is the cleanest, hence River water.
Question 306 of 455
📘 CLASS XII
Microbes In Human Welfare
The most polluted water sample, Sample C (400 mg/L), corresponds to _____.
Sample C (400 mg/L) has the highest BOD, indicating the highest polluting potential, which is the untreated sewage water.
Question 307 of 455
📘 CLASS XII
Microbes In Human Welfare
The purpose of the anaerobic sludge digesters is to allow anaerobic bacteria to digest the ____ in the sludge.
Other kinds of bacteria, which grow anaerobically, digest the bacteria and the fungi in the sludge.
Question 308 of 455
📘 CLASS XII
Microbes In Human Welfare
In the rumen of cattle, methanogens play an important role in the breakdown of _____.
In rumen, these bacteria help in the breakdown of cellulose.
Question 309 of 455
📘 CLASS XII
Microbes In Human Welfare
Our soil is also polluted through our use of _____ to remove weeds.
Our soil is also polluted through our use of weedicides to remove weeds.
Question 310 of 455
📘 CLASS XII
Microbes In Human Welfare
The eradication of pests is considered undesirable by organic farmers because without them, beneficial _____ insects would not be able to survive.
Without pests, the beneficial predatory and parasitic insects which depend upon them as food or hosts would not be able to survive.
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