Which instrument is commonly used to create rhythm in a song?

The core elements of the rhythm section are usually the drum kit and bass. The drums and bass provide the basic pulse and groove of a song. The section is augmented by other instruments such as keyboard instruments and guitars that are used to play the chord progression upon which the song is based. The bass instrument (either double bass, or electric bass guitar, or another low-register instrument such as the synth bass, depending on the group and its style of music) plays the low-pitched bassline. The bassline is a musical part that supports the chord progression, typically by playing a musically interesting bassline that outlines the important notes of the harmony, often by emphasizing the root, fifth, and third of each chord.