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

The correct option is 2 only.

Let us analyze both statements step-by-step to understand the logic behind the correct answer:

Statement 1: "Adenoviruses have single-stranded DNA genomes whereas retroviruses have double-stranded DNA genomes."
This statement is incorrect.
- Adenoviruses are non-enveloped viruses that possess a double-stranded DNA (dsDNA) genome.
- Retroviruses (such as HIV) are RNA viruses that possess a single-stranded RNA (ssRNA) genome (which uses reverse transcriptase to convert its RNA into DNA during replication inside the host cell).

Statement 2: "Common cold is sometimes caused by an adenovirus whereas AIDS is caused by a retrovirus."
This statement is correct.
- Common cold can be caused by various viruses, most commonly rhinoviruses, but adenoviruses are also a known cause of respiratory illnesses including common cold-like symptoms.
- Acquired Immunodeficiency Syndrome (AIDS) is caused by Human Immunodeficiency Virus (HIV), which is a classic example of a retrovirus.

Therefore, only Statement 2 is correct.