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.
Not all RNA viruses are retroviruses, e.g., the measles virus and flu virus are RNA viruses, but not retroviruses. There are three families of retroviruses: oncoviruses (causing cancer), lentiviruses (slow viruses, of which HIV is one), and foamy viruses or spumaviruses (about which much less is known).