Which of the following enzymes is unique to retroviruses and is essential for their replication cycle, converting their RNA genome into a DNA intermediate?

Explanation

Reverse transcriptase is an enzyme unique to retroviruses (like HIV) that catalyzes the synthesis of DNA from an RNA template. This process, known as reverse transcription, is a crucial step in the retroviral life cycle, allowing the viral genetic information to be integrated into the host cell's genome. RNA replicase is found in some RNA viruses but synthesizes RNA from an RNA template. DNA polymerase synthesizes DNA from a DNA template. RNA ligase joins RNA fragments.