Explain simply why Paul McCartney and John Lennon is the correct answer to: Passage: "Yellow Submarine" is a 1966 song by the Beatles, written by Paul McCartney and John Lennon, with lead vocals by Ringo Starr. It was included on the Revolver (1966) album and issued as a single, coupled with "Eleanor Rigby". The single went to number one on every major British chart, remained at number one for four weeks, and charted for 13 weeks. It won an Ivor Novello Award "for the highest certified sales of any single issued in the UK in 1966". In the US, the song peaked at number two on the Billboard Hot 100 chart and became the most successful Beatles song to feature Starr as lead vocalist.

Question: Based on this passage, who wrote we all live in a yellow submarine?. Explanation:
The important part for answering this question is: "Yellow Submarine" is a 1966 song by the Beatles, written by Paul McCartney and John Lennon, with lead vocals by Ringo Starr.