Answer:
3 genes.
Step-by-step explanation:
Retroviruses consist of a dimer of single-stranded positive sense RNA enclosed in a capsid of a lipid bilayer envelope and contain a reverse transcriptase (RT) enzyme.5The retrovirus genome is composed of 3 genes (gag, Poland env) enclosed between 2 long terminal repeats: pol(polymerase) has RT and integrase function, gag (group antigens) is a polyprotein with processed matrix and core proteins, and unencodes envelope proteins (Figure 1A).
Hope this helps! :)