UPSC CSE Prelims
Question 17
Consider the following statements:
- Adenoviruses have single-stranded DNA genomes whereas retroviruses have double-stranded DNA genomes.
- Common cold is sometime caused by an adenovirus whereas AIDS is caused by a retrovirus.
Which of the statements given above is/are correct?
View correct answer and explanation
Correct answer: B
Correct Option: B (2 only)
Explanation: Adenoviruses carry double-stranded DNA and HIV is a retrovirus with an RNA genome; adenoviruses can cause colds, while HIV causes AIDS.
Statement / Pair / Item-wise Analysis:
1. Incorrect / does not qualify - Adenovirus DNA is double-stranded; retroviruses generally have single-stranded RNA genomes.
2. Correct / qualifies - Some colds are caused by adenoviruses; HIV is a retrovirus causing AIDS.
Option-wise Analysis:
A. Incorrect-includes item 1, which is not valid (Adenovirus DNA is double-stranded; retroviruses generally have single-stranded RNA genomes); omits valid item 2 (Some colds are caused by adenoviruses; HIV is a retrovirus causing AIDS).
B. Correct-selects exactly the supported statements/items: 2.
C. Incorrect-includes item 1, which is not valid (Adenovirus DNA is double-stranded; retroviruses generally have single-stranded RNA genomes).
D. Incorrect-omits valid item 2 (Some colds are caused by adenoviruses; HIV is a retrovirus causing AIDS).