UPSC CSE Prelims
Question 8
Consider the following statements :
- Some microorganisms can grow in environments with temperature above the boiling point of water.
- Some microorganisms can grow in environments with temperature below the freezing point of water.
- Some microorganisms can grow in highly acidic environment with a pH below 3.
How many of the above statements are correct?
View correct answer and explanation
Correct answer: C
Correct Option: C (All three)
Explanation: Extremophilic microorganisms tolerate high heat, sub-zero conditions or strong acidity; each extreme has specialist species.
Statement / Pair / Item-wise Analysis:
1. Correct/True - Certain hyperthermophilic microbes survive above 100°C in high-pressure environments.
2. Correct/True - Psychrophiles can grow below 0°C, for instance in salty or unfrozen microscopic water pockets.
3. Correct/True - Acidophiles tolerate strongly acidic environments, including pH below 3.
Option-wise Analysis:
A. Incorrect-it counts 1, but items 1, 2, 3 qualify, giving 3.
B. Incorrect-it counts 2, but items 1, 2, 3 qualify, giving 3.
C. Correct-exactly 3 of the 3 listed items satisfy the condition.
D. Incorrect-it counts 0, but items 1, 2, 3 qualify, giving 3.