Context and question: During the 18th century, systems of plant identification were developed comparable to dichotomous keys, where unidentified plants are placed into taxonomic groups (e.g. family, genus and species) by making a series of choices between pairs of characters. The choice and sequence of the characters may be artificial in keys designed purely for identification (diagnostic keys) or more closely related to the natural or phyletic order of the taxa in synoptic keys. By the 18th century, new plants for study were arriving in Europe in increasing numbers from newly discovered countries and the European colonies worldwide. In 1753 Carl von Linné (Carl Linnaeus) published his Species Plantarum, a hierarchical classification of plant species that remains the reference point for modern botanical nomenclature. This established a standardised binomial or two-part naming scheme where the first name represented the genus and the second identified the species within the genus. For the purposes of identification, Linnaeus's Systema Sexuale classified plants into 24 groups according to the number of their male sexual organs. The 24th group, Cryptogamia, included all plants with concealed reproductive parts, mosses, liverworts, ferns, algae and fungi.
What is the term for keys used for identification?
Answer: diagnostic keys
Context and question: Some rock musicians today use mandolins, often single-stringed electric models rather than double-stringed acoustic mandolins. One example is Tim Brennan of the Irish-American punk rock band Dropkick Murphys. In addition to electric guitar, bass, and drums, the band uses several instruments associated with traditional Celtic music, including mandolin, tin whistle, and Great Highland bagpipes. The band explains that these instruments accentuate the growling sound they favor. The 1991 R.E.M. hit "Losing My Religion" was driven by a few simple mandolin licks played by guitarist Peter Buck, who also played the mandolin in nearly a dozen other songs. The single peaked at No. 4 on the Billboard Hot 100 chart (#1 on the rock and alternative charts), Luther Dickinson of North Mississippi Allstars and The Black Crowes has made frequent use of the mandolin, most notably on the Black Crowes song "Locust Street." Armenian American rock group System of A Down makes extensive use of the mandolin on their 2005 double album Mezmerize/Hypnotize. Pop punk band Green Day has used a mandolin in several occasions, especially on their 2000 album, Warning. Boyd Tinsley, violin player of the Dave Matthews Band has been using an electric mandolin since 2005. Frontman Colin Meloy and guitarist Chris Funk of The Decemberists regularly employ the mandolin in the band's music. Nancy Wilson, rhythm guitarist of Heart, uses a mandolin in Heart's song "Dream of the Archer" from the album Little Queen, as well as in Heart's cover of Led Zeppelin's song "The Battle of Evermore." "Show Me Heaven" by Maria McKee, the theme song to the film Days of Thunder, prominently features a mandolin.
What American rock band has extensive use of mandolins? 
Answer: System of A Down
Context and question: The patron saint of Palermo is Santa Rosalia, who is widely revered. On 14 July, people in Palermo celebrate the annual Festino, the most important religious event of the year. The Festino is a procession which goes through the main street of Palermo to commemorate the miracle attributed to Santa Rosalia who, it is believed, freed the city from the Black Death in 1624. Her remains were discovered in a cave on Monte Pellegrino, and her remains were carried around the city three times, banishing the plague. There is a sanctuary marking the spot where her remains were found which can be reached via a scenic bus ride from the city.
When is Palermo's most important religious event of the year held?
Answer:
14 July