But Social Security was never meant to be the only source. of income for people when they retire. Social Security. replaces about 40 percent of an average wage earnerâs income. after retiring, and most financial advisors say retirees will. need 70 percent or more of pre-retirement earnings to live. comfortably.
DNA viruses. Originally viruses were grouped and named according to the disease they cause, even if they are not closely related. For example Hepatitis A is an RNA virus and Hepatitis B is a DNA virus, but they both cause liver disease.Nowadays, however, viruses are grouped by their shared characteristics in much the same way as plants and animals are. All but one of the DNA virus families use double stranded DNA as their infectious 'code'.riginally viruses were grouped and named according to the disease they cause, even if they are not closely related. For example Hepatitis A is an RNA virus and Hepatitis B is a DNA virus, but they both cause liver disease.
Retrovirus. Retroviruses are enveloped viruses that belong to the viral family Retroviridae. A retrovirus is an RNA virus that is duplicated in a host cell using the reverse transcriptase enzyme to produce DNA from its RNA genome. On infection, the single-stranded RNA viral genome and the enzyme enters the host cell.he viral genome is released into the host cell, from which a copy of DNA is made by the help of the enzyme reverse transcriptase. The cDNA is integrated into the host chromosome. The virus remains unexpressed until the host's immune system is stimulated.