Cognitive password set of questions and answers that users would be expected to know and could easily recall. At the core of a cognitive password system lies the questions. These questions were designed to be more memorable than the standard username/password authentication method. As such, a measure of the strength of a cognitive password is the memorability/guessability ratio. Questions developed for cognitive password systems are classified as being either fact or opinion based. Fact based systems have questions with answers that are considered independent of an individual's feelings such as "What is the name of the high school you attended?". Opinion based
Most recent common ancestor Most recent common ancestor In biology and genealogy, the most recent common ancestor (MRCA, also last common ancestor (LCA), or concestor) of any set of organisms is the most recent individual from which all the organisms are directly descended. The term is also used in reference to the ancestry of groups of genes (haplotypes) rather than organisms. The MRCA of a set of individuals can sometimes be determined by referring to an established pedigree. However, in general, it is impossible to identify the exact MRCA of a large set of individuals, but an estimate of the time at which the