Consider the following statements:1.Adenoviruses have single- stranded DNA genomes whereas retroviruses have double-stranded DNA genomes.2.Common cold is sometime caused by an adenovirus whereas AIDS is caused by a retrovirus.Which of the statements given above is/are correct?

1. A

   1 only

   1 only. Adenoviruses are dsDNA; retroviruses are RNA viruses, not dsDNA genomes as stated.

2. B

   2 only

   2 only. Some common colds are adenovirus; AIDS is HIV, a retrovirus.

3. C

   Both 1 and 2

   Both. Statement 1 swaps the nucleic acids.

4. D

   Neither 1 nor 2

   Neither. Statement 2 holds.

Summary. Official key is (b) 2 only. Adenovirus: double-stranded DNA. Retrovirus: RNA genome and reverse transcriptase. Cold can be adenovirus; AIDS is a retrovirus. Statement 1 is inverted.