What are the functions of rhythm?

In the early days of top-40 (popular music), kids were asked to rate their favorite songs, and they would often mention that a song "had a good beat" and was therefore easy to dance to. That beat-- the rhythm of a song-- is what holds it together. Not all rhythm is fast-- it can be slow, it can change tempo, but without rhythm, all other elements of a work of music would break down. Melodies and chords would be dimensionless sequences of notes, and tempo would be meaningless. Rhythm gives music life, whether one is listening to it, singing it, playing it or dancing to it.