Mercy Mercy Me (The Ecology)

The second single from What's Going On was written solely by Gaye. He plays piano and Mellotron, the Andantes join him on harmony vocals, Paul Riser and David Van De Pitte conducted the strings, and Wild Bill Moore plays the tenor saxophone solo. The bass line is by Bob Babbitt rather than James Jamerson. It reached number four on the Hot 100 and spent two weeks at number one on the R&B chart in August 1971, and it was Gaye's second million-seller from the album. Cash Box called it a similar chugging ballad to the title song, and it entered the Grammy Hall of Fame in 2002. The B-side, Sad Tomorrows, was an early version of Flyin' High.

Robert Palmer joined it in a medley with Gaye's I Want You in December 1990, reaching number 16 on the Hot 100 and number nine in the United Kingdom. The Strokes recorded it in 2006 as a B-side with Eddie Vedder sharing the vocals.