A retrovirus is a type of RNA virus that inserts a copy of its genome into the DNA of a host cell that it invades resulting in changing the original genome of that cell. There are about three examples of retroviruses, they are
* HIV
* Human T-lymphotropic virus type 1 (HTLV-1)
* Human T-lymphotropic virus type 2 (HTLV-II)
It should be understood that there is a difference between virus and retrovirus. This is that a retrovirus inserts its genome into the host's genome unlike the virus.
Segmented viruses are viruses that package all of their genome segments into a single particle.
In this case, these viruses have high rate rate of genetic mutation and adaptation.