Give reasons:
Retrovirus is considered to be an exception to the central dogma.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Central Dogma**: The central dogma of molecular biology describes the flow of genetic information within a biological system. It states that information is transferred from DNA to RNA (transcription) and then from RNA to proteins (translation). Additionally, DNA can replicate itself.

2. **Identifying the Nature of Retroviruses**: Retroviruses are a class of viruses that contain RNA as their genetic material instead of DNA. This is a key characteristic that sets them apart from organisms that follow the central dogma.

3. **Reverse Transcription Process**: Retroviruses have a unique mechanism called reverse transcription. In this process, the RNA genome of the retrovirus is converted back into DNA by an enzyme called reverse transcriptase. This is the opposite of the typical flow of information described by the central dogma.

...