The enzyme reverse transcriptase, essentially found in all retroviruses, is

Explanation

Reverse transcriptase is an enzyme found in all retroviruses that enables them to replicate by converting their RNA genome into complementary DNA (cDNA). This DNA is then integrated into the host cell's genome, allowing the virus to use the cell's machinery for producing viral proteins and new virus particles. By reversing the normal flow of genetic information (RNA → DNA), reverse transcriptase is essential for viral survival and has also become an important tool in molecular biology research.