<human>: Rubber Soul is the sixth studio album by the English rock band the Beatles. It was released on 3 December 1965 in the United Kingdom, on EMI's Parlophone label, accompanied by the non-album double A-side single "Day Tripper" / "We Can Work It Out". The original North American version of the album was altered by Capitol Records to include a different selection of tracks.

Most of the album's songs were composed soon after the Beatles' return to London after their North American tour. The Beatles expanded their sound on the album, with influences drawn from African-American soul music, the contemporary folk rock of Bob Dylan and the Byrds, and the Who. Rubber Soul also saw the band expanding rock and roll's instrumental resources, most notably on "Norwegian Wood (This Bird Has Flown)" through George Harrison's use of the Indian sitar. Having been introduced to the instrument on the set of the band's 1965 film Help!, Harrison's interest was fuelled by fellow Indian music fans Roger McGuinn and David Crosby of the Byrds, partway through the Beatles' August 1965 US tour.  Taking support from French and Greek-influenced modalities for guitar lines on "Michelle" and "Girl", using fuzz bass on "Think for Yourself", and employing a piano made to sound like a baroque harpsichord on the instrumental bridge of "In My Life" added to the exotic brushstrokes on the album. During the sessions, the Beatles also made use of harmonium, marking that instrument's introduction into rock music. Lennon, McCartney and Harrison's three-part harmony singing was another musical detail that came to typify the Rubber Soul sound. Author Andrew Grant Jackson describes Rubber Soul as a "synthesis of folk, rock, soul, baroque, proto-psychedelia, and the sitar". According to The Encyclopedia of Country Music, building on the band's 1964 track "I Don't Want to Spoil the Party", the album can be seen in retrospect as an early example of country rock, anticipating the Byrds' Sweetheart of the Rodeo album.  Ringo Starr had frequently augmented Beatles tracks with percussion instruments such as maracas or tambourine, but on "I'm Looking Through You" he unusually used taps on a box of matches, perhaps influenced by a similar trick accomplished by Gene Krupa in the 1941 film Ball of Fire. In the main guitar riff to "If I Needed Someone", the Beatles returned the compliment paid to them earlier in 1965 by the Byrds, whose jangly guitar-based sound McGuinn had sourced from Harrison's playing the previous year. For the country-styled "What Goes On", Starr received his first songwriting credit (as Richard Starkey), as a co-composer with Lennon and McCartney. CANNOTANSWER

Answer the following question by taking a quote from the article: What was significant about their music?
<bot>: saw the band expanding rock and roll's instrumental resources,