One of my favorite bands of all times is the Beatles. They totatally revolutionized music.
They certainly did! Their music and experimentation were vital to the development of the 60s counterculture.
It was! Some of my favorite songs was Come Together and Hey Jude! 
They are great songs. Hey Jude was originally called Hey Jules. McCartney wrote it for John Lennon's son Julian during Julian's parents' divorce.