Explanation
- A
Only one
Only one. Extremophiles cover heat, cold and acid.
- B
Only two
Only two. All three habitats have microbes.
- C
All three
All three. Hyperthermophiles above 100 °C, psychrophiles below 0 °C, acidophiles below pH 3.
- D
None
None. Each statement is standard microbiology.
Summary. Official key is (c) all three. Pyrococcus and similar archaea grow above the boiling point (under pressure). Psychrophiles grow in sea ice. Acidithiobacillus and Picrophilus grow below pH 3. All three statements hold.
Same topic · past papers
UPSC has asked this before
These previous-year questions sit on the same topic. Open one to practise the earlier ask.
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2017 · Q14 · General Studies · 2 marks
In the context of solving pollution problems, what is/are the advantage/advantages of bioremediation technique? 1. It is a technique for cleaning up pollution by enhancing the same biodegradation process that occurs in nature. 2. Any contaminant with heavy metals such as cadmium and lead can be readily and completely treated by bioremediation using microorganisms. 3. Genetic engineering can be used to create microorganisms specifically designed for bioremediation. Select the correct answer using the code given below: -
2025 · Q29 · General Studies · 2 marks
Consider the following statements: I. Without the atmosphere, temperature would be well below freezing point everywhere on the Earth's surface. II. Heat absorbed and trapped by the atmosphere maintains our planet's average temperature. III. Atmosphere's gases, like carbon dioxide, are particularly good at absorbing and trapping radiation. Which of the statements given above are correct?