Virus and spyware definitions are files that act like an encyclopedia of known malicious software, including viruses, spyware, and other potentially unwanted software.
Highly accurate DNA parental testing became available in the 1980s with the development of RFLP. In the 1990s, PCR, developed in 1983, became the standard method for DNA parental testing. A simpler, faster, and more accurate method of testing than RFLP, it has an exclusion rate of 99.99% or higher.
Originally, senators were selected by the state legislatures, not by popular elections. By the early years of the 20th century, the legislatures of as many as 29 states had provided for popular election of senators by referendums. Popular election to the Senate was standardized nationally in 1913 by the ratification of the Seventeenth Amendment.