Question: Are Adam Gontier and Björk both singers?

full_context: Document 1: Three Days Grace: Three Days Grace is a Canadian rock band formed in Norwood, Ontario in 1997. Based in Toronto, the band's original line-up consisted of guitarist and lead vocalist Adam Gontier, drummer and backing vocalist Neil Sanderson, and bassist Brad Walst. In 2003, Barry Stock was recruited as the band's lead guitarist. In 2013, Gontier left the band and was replaced by My Darkest Days' vocalist Matt Walst, who is also bassist Brad Walst's brother.
Document 2: Homogenic: Homogenic is the third international solo album by Icelandic musician Björk, released in September 1997. Produced by Björk, Mark Bell, Guy Sigsworth, Howie B and Markus Dravs, it was released on One Little Indian Records. The music of "Homogenic" was a new style for Björk, focusing on similar-sounding music combining electronic beats and string instruments with songs in tribute to her native country Iceland. "Homogenic" was originally to be produced in her home in London, but was later recorded in Spain. "Homogenic" marked the first of several production collaborations between Björk and Mark Bell, whom Björk would cite as a major influence on her musical career. The album peaked at number twenty-eight on the "Billboard" 200, and at number four on the UK Albums Chart.
Document 3: Saint Asonia: Saint Asonia (stylized as SΔINT ΔSONIΔ) is a Canadian-American rock supergroup originally consisting of former Three Days Grace frontman Adam Gontier (lead vocals, rhythm guitar), Mike Mushok from Staind (lead guitar), Corey Lowery from Dark New Day, Eye Empire, Switched, Sevendust, Stereomud and Stuck Mojo (bass, backing vocals), and Rich Beddoe from Finger Eleven (drums). In 2017, Beddoe left the band and was replaced by Mushok's Staind bandmate Sal Giancarelli. Formed in Toronto, Ontario, Canada in 2015 after Gontier's departure from Three Days Grace, they released their debut studio album "Saint Asonia" on July 31, 2015.
Document 4: Art of Dying (band): Art of Dying is a Canadian rock band fronted by Jonny Hetherington. The band is currently signed to Better Noise Records. Bassist Cale Gontier is the cousin of Adam Gontier, the lead singer of Saint Asonia and former lead singer of Three Days Grace. Prior to joining the band, Gontier and guitarist Tavis Stanley played in another band, Thornley.
Document 5: Tappi Tíkarrass: Tappi Tíkarrass was an Icelandic punk band which added elements of funk, rock and jazz to their music, marking a difference from other traditional bands at that time. The band is also considered the first serious music project of now renowned singer Björk Guðmundsdóttir.
Document 6: Björk: Björk Guðmundsdóttir (] , born 21 November 1965), known as Björk ( ), is an Icelandic singer, songwriter, actress, record producer, and DJ. Over her four-decade career, she has developed an eclectic musical style that draws on a wide range of influences and genres spanning electronic, pop, experimental, classical, trip hop, IDM, and avant-garde styles. She initially became known as the lead singer of the alternative rock band The Sugarcubes, whose 1987 single "Birthday" was a hit on US and UK indie stations and a favorite among music critics. Björk embarked on a solo career in 1993, coming to prominence as a solo artist with albums such as "Debut" (1993), "Post" (1995), and "Homogenic" (1997), while collaborating with a range of artists and exploring a variety of multimedia projects.
Document 7: Human (Three Days Grace album): Human is the fifth studio album by Canadian rock band Three Days Grace. The album was released on March 31, 2015 through RCA Records. This is the group's first album without original lead singer Adam Gontier, and the first with former My Darkest Days lead singer Matt Walst. It debuted at No. 16 on the ""Billboard" 200.
Document 8: Debut (Björk album): Debut is the first international solo studio album by Icelandic recording artist Björk. The album was released in July 1993 on One Little Indian and Elektra Records, and was produced by Björk in collaboration with artist Nellee Hooper. Her first recording following the dissolution of her previous band the Sugarcubes, the album departed from the rock-oriented style of her previous work and instead drew on an eclectic variety of styles across electronic pop, house music, jazz and trip hop.
Document 9: Post (Björk album): Post is the second solo studio album by Icelandic musician Björk. The album was released in June 1995 through One Little Indian in the United Kingdom and Elektra Records in the United States. Unlike her previous release "Debut"—which was almost entirely produced by Nellee Hooper—"Post" is characterised by more collaborative efforts, including production by Hooper, 808 State's Graham Massey, and former Massive Attack member Tricky. Moreover, Björk co-produced every song on the album. "Post" received widespread critical acclaim from reviewers and was a commercial success, charting at number 2 in the United Kingdom and 32 in the United States. It was certified gold in New Zealand and Sweden, and platinum in Australia, Canada, the United States, and the United Kingdom. "Telegram", a remix album of songs from "Post", was released in 1996.
Document 10: List of songs recorded by Björk: Icelandic singer and songwriter Björk has recorded more than one hundred songs for eight studio albums, two soundtrack albums, a compilation album, five remix albums and two collaboration albums. She is the sole writer and producer of most of the songs included in her albums. She also sometimes plays instruments during her recording sessions. Moreover, she has provided credited and uncredited contributions on songs recorded by other artists, including background vocals, songwriting, remixing and production.
Document 11: Devin Townsend: Devin Garrett Townsend (born May 5, 1972) is a Canadian musician, songwriter and record producer. He founded extreme metal band Strapping Young Lad and was its primary songwriter, vocalist, and guitarist in from 1994 to 2007, and has an extensive career as a solo artist.
Document 12: Adam Gontier: Adam Wade Gontier (born May 25, 1978) is a Canadian singer, songwriter and musician. He is the lead singer, rhythm guitarist and main songwriter for Saint Asonia, but is best known as the former lead singer, rhythm guitarist and main songwriter of the Canadian rock band Three Days Grace. Gontier left Three Days Grace on January 9, 2013. In addition to his work with Three Days Grace, he has been involved in collaborations with other bands including Art of Dying and Apocalyptica.
Document 13: Saint Asonia (album): Saint Asonia is the self-titled debut studio album by rock supergroup Saint Asonia. First announced via YouTube through a teaser in early May 2015, the first single "Better Place" was released on May 16, 2015. This also confirmed the group's lineup, with Adam Gontier as the frontman, Mike Mushok being the guitarist, Corey Lowery as the bassist and Rich Beddoe as the drummer. The album was released on July 31, 2015 through RCA Records. Gontier's uncle Tom Duffy provided the bass tracks for some of the songs from the album, while Lowery was hired afterward. This is also the only studio album from the band to feature drummer Rich Bedoe before he confirmed his departure in 2017
Document 14: List of awards and nominations received by Björk: Björk is a singer-songwriter from Reykjavík, Iceland. Her debut album, "Björk", considered juvenilia, was released in 1977 by the Fálkinn record label. Her subsequent eight studio albums were released by One Little Indian Records: "Debut" (1993), "Post" (1995), "Homogenic" (1997), "Vespertine" (2001), "Medúlla" (2004), "Volta" (2007), "Biophilia" (2011) and "Vulnicura" (2015). Six of her albums have entered the top 10 in the UK Albums Chart, while "Volta", is her only album to reach the top 10 in the "Billboard" 200. Björk's record label, One Little Indian Records, reported that she has sold more than 20 million albums worldwide.
Document 15: Adam Jones (musician): Adam Thomas Jones (born January 15, 1965) is a three-time Grammy Award-winning American musician and visual artist, best known for his position as the guitarist for Tool. Jones has been rated the 75th Greatest Guitarist of all time by the "Rolling Stone" and placed ninth in "Guitar World's" Top 100 Greatest metal Guitarists. Jones is also the director of the majority of Tool's music videos.
ground_truth: yes