Background: The Roots is an American hip hop band, formed in 1987 by Tariq "Black Thought" Trotter and Ahmir "Questlove" Thompson in Philadelphia, Pennsylvania, United States. The Roots are known for a jazzy and eclectic approach to hip-hop featuring live musical instruments. Malik B., Leonard "Hub" Hubbard, and Josh Abrams were added to the band (formerly named "The Square Roots"). Since its first independent album-length release the band has released 10 studio albums, two EPs, two collaboration albums (with other artists), and also collaborated on recordings and in live shows with a wide variety of artists in many musical genres.
Context: The Roots' original lineup included Tariq "Black Thought" Trotter (MC) and Ahmir "Questlove" Thompson (drums), classmates at the Philadelphia High School for Creative and Performing Arts. As they began to play at school and on local streets, they added bassist Josh "The Rubberband" Abrams, who went on to form the jazz group The Josh Abrams Quartet. They later added another MC, Malik Abdul Basit-Smart ("Malik B.") and Leonard Nelson "Hub" Hubbard (bass), and Scott Storch (keyboards). Kenyatta "Kid Crumbs" Warren (MC) was in the band for Organix, the Roots' first album release. Another MC, Dice Raw, joined the band in cameo appearances on later albums. The band filled Storch's position with Kamal Gray (keyboards), who continues in that capacity. Kamal Gray did not play with the Roots on Late Night With Jimmy Fallon between April or May and early September 2012. His absence was not publicly explained, however on the September 17, 2012 (NBC's 'Late Night' 700th) episode, Gray returned to the group. Beatboxer Rahzel was a band member from 1995 to 1999. Alongside Rahzel was turntablist/vocalist Scratch, who also DJ'd in live concerts. However Scratch left abruptly in 2003. Malik B. left the group in 1999 due to personal reasons but continued to record, making occasional cameos on some albums. Guitarist Ben Kenney, had a brief stint with the group and contributed to the Phrenology album, but left to join Incubus as bassist. Percussionist Frank Knuckles joined the lineup in 2002 and guitarist Kirk "Captain Kirk" Douglas replaced Kenney. Vocalist Martin Luther toured with the Roots in 2003 and 2004 and contributed to the Tipping Point album. The group announced in August 2007 that its longtime bassist Leonard Hubbard was leaving. Owen Biddle was the band's bassist in 2007-2011. The band announced on August 25, 2011 that Owen Biddle left the band, replaced by Mark Kelley. On The Tonight Show Starring Jimmy Fallon, James Poyser plays additional keyboards. Because most of the band members hail from Philadelphia and its surrounding area, they showed their support for the Phillies during the 2009 World Series against the Yankees, displaying Phillies memorabilia when performing on Late Night with Jimmy Fallon. On the episode which aired the day after the Yankees clinched the title, Questlove stated "No comment!" on the show's intro (when he usually states the episode number), and had a Yankees logo purposely displayed upside-down on his drumset. In 2010, the group showed support for the Flyers during their run to the Stanley Cup Final by having the team logo on their drumset, and again in 2014 when the Flyers faced the New York Rangers in the first round of the playoffs on The Tonight Show Starring Jimmy Fallon. In April 2017, Frank Knuckles left the Roots due to family issues, and has not appeared on The Tonight Show since then. Later in August 2017, Knuckles sued Questlove, Black Thought and the band manager Shawn Gee over unpaid royalties. In June 2017, Questlove announced in an interview that producer and performer Stro Elliot is an official member of the Roots.
Question: Who else dissapeared
Answer: who continues in that capacity. Kamal Gray did not play with the Roots on Late Night With Jimmy Fallon between April or May and early September 2012.

Background: Earth Crisis is an American metalcore band from Syracuse, New York, active from 1989 until 2001, reuniting in 2007. Since 1993 the band's longest serving members are vocalist Karl Buechner, guitarist Scott Crouse, bassist Ian Edwards and drummer Dennis Merrick. Their third guitarist Erick Edwards joined the band in 1998. The band has released eight studio albums, three compilations, two live albums and six music videos.
Context: The name of the band, Earth Crisis, indicates how their members see the current state of the planet and in their lyrics they seek to offer solutions to it; these are either "educational" or encourage direct-action. Most of them focus on rejection of recreational drugs, animal products, animal testing, industrial livestock production, illegal drug trade and an impending earth's doom caused by wars or an ecological collapse. On the other hand, they promote straight edge, veganism, self-empowerment and organizations such as Earth First!, Sea Shepherd Conservation Society and the Animal Liberation Front. In the words of the academic Jonathan Pieslak, some of their lyrics "read like passages" taken from "direct-action essays" of these institutions. Other subjects include criticism against white supremacy and, especially on Breed the Killers, oppressive governments. 2000's record Slither incorporated more topical issues, such as genetic engineering and second amendment rights. Their seventh and eighth albums, Neutralize the Threat and Salvation of Innocents, are concept albums entirely dedicated to real-life vigilantes and animal rights/anti-vivisection, respectively. The albums All Out War, Gomorrah's Season Ends and Breed the Killers included essays that delve into their lyrics and beliefs. According to the sociologist Ross Haenfler, Earth Crisis combined "youth crew's outspoken commitment to straight edge with Manliftingbanner's direct politics". In a 1998 interview with Roadrunner Records, Karl Buechner described Earth Crisis' philosophy: "I want to boil it down to one notion: personal accountability. Respect for yourself, respect for the lives of innocent beings around us." He added that "Just being drug-free doesn't make you a good person, you need to use that clarity of the mind to become actively involved in the struggle that is being waged for earth, human and animal liberation." Their message disjoined from the "posicore" attitudes in its advocation for violent direct action. However, they believe that it must be used only as a last resort: "destruction and violence are the last thing I want to see but tragically, they are sometimes necessary. We place so far greater value on the lives of the innocent beings than any type of worth that could be put upon someone who's sadistic or greedy and doesn't want to change their profit system", said Buechner. The band cited authors Peter Singer, John Robbins and Huey P. Newton as inspirations. In their live shows, there is usually literature about PETA, Greenpeace and others distributed. They have been longtime supporters for organizations such as the Animal Defense League, having done several benefit concerts for them. Nevertheless, they are not part of any of these groups or a political party: "We're about things we're interested in and we sing about things that happen politically, but we're not left-core or right wing. We don't want to get tangled up in someone else's agenda, which can happen if you join up in certain organizations." Earth Crisis was occasionally misidentified with the hardline subculture, but they are not against homosexuality and believe that abortion should remain as an option in some instances. They also do not have a religious agenda and think that that is mainly a personal choice.
Question: Do they sing about other topics?
Answer:
Most of them focus on rejection of recreational drugs, animal products, animal testing,