Questions regarding retroviruses

[poisson]

DNA viruses transcribe RNA to produce proteins.

Why can't retroviruses use its original RNA to produce protein?

Why do they need to go through a "redundant" step of RNA then DNA then RNA?

Thanks for answering.

[david23]

good question

Remember the retroviruses go 1 more step and that is they integrate their DNA into the host. Once it's integrated that DNA stays for life (of the cell) You will get more copies of the virus as a result. If the virus use its RNA alone at some point that RNA is going to degrade, remember that RNA is unstable.

[JackBean]

David wrote it already, but to make it more clear - two factors: number of copies and stability.