Problem: In 1671, Robert Boyle discovered and described the reaction between iron filings and dilute acids, which results in the production of hydrogen gas. In 1766, Henry Cavendish was the first to recognize hydrogen gas as a discrete substance, by naming the gas from a metal-acid reaction "flammable air". He speculated that "flammable air" was in fact identical to the hypothetical substance called "phlogiston" and further finding in 1781 that the gas produces water when burned. He is usually given credit for its discovery as an element. In 1783, Antoine Lavoisier gave the element the name hydrogen (from the Greek ὑδρο- hydro meaning "water" and -γενής genes meaning "creator") when he and Laplace reproduced Cavendish's finding that water is produced when hydrogen is burned.
What year was the discovery of hydrogen gas?
The answer is the following: 1671

Problem: Mass incarceration in the United States disproportionately impacts African American and Latino communities. Michelle Alexander, author of The New Jim Crow: Mass Incarceration in the Age of Colorblindness (2010), argues that mass incarceration is best understood as not only a system of overcrowded prisons. Mass incarceration is also, "the larger web of laws, rules, policies, and customs that control those labeled criminals both in and out of prison." She defines it further as "a system that locks people not only behind actual bars in actual prisons, but also behind virtual bars and virtual walls", illustrating the second-class citizenship that is imposed on a disproportionate number of people of color, specifically African-Americans. She compares mass incarceration to Jim Crow laws, stating that both work as racial caste systems.
What type of caste system is mass incarceration compared to?
The answer is the following: racial

Problem: Today Saint Helena has its own currency, the Saint Helena pound, which is at parity with the pound sterling. The government of Saint Helena produces its own coinage and banknotes. The Bank of Saint Helena was established on Saint Helena and Ascension Island in 2004. It has branches in Jamestown on Saint Helena, and Georgetown, Ascension Island and it took over the business of the St. Helena government savings bank and Ascension Island Savings Bank.
The Saint Helena pound is at parity with what other currency?
The answer is the following: pound sterling

Problem: In the new commercial climate glam metal bands like Europe, Ratt, White Lion and Cinderella broke up, Whitesnake went on hiatus in 1991, and while many of these bands would re-unite again in the late 1990s or early 2000s, they never reached the commercial success they saw in the 1980s or early 1990s. Other bands such as Mötley Crüe and Poison saw personnel changes which impacted those bands' commercial viability during the decade. In 1995 Van Halen released Balance, a multi-platinum seller that would be the band's last with Sammy Hagar on vocals. In 1996 David Lee Roth returned briefly and his replacement, former Extreme singer Gary Cherone, was fired soon after the release of the commercially unsuccessful 1998 album Van Halen III and Van Halen would not tour or record again until 2004. Guns N' Roses' original lineup was whittled away throughout the decade. Drummer Steven Adler was fired in 1990, guitarist Izzy Stradlin left in late 1991 after recording Use Your Illusion I and II with the band. Tensions between the other band members and lead singer Axl Rose continued after the release of the 1993 covers album The Spaghetti Incident? Guitarist Slash left in 1996, followed by bassist Duff McKagan in 1997. Axl Rose, the only original member, worked with a constantly changing lineup in recording an album that would take over fifteen years to complete.
What former member of Extreme briefly served as the lead singer for Van Halen?
The answer is the following:
Gary Cherone