What are the differences between gta online and story mode?

The evidence provided describes Grand Theft Auto: San Andreas as a 2004 action-adventure game developed by Rockstar North and published by Rockstar Games. It is the fifth main entry in the Grand Theft Auto series, set in the fictional state of San Andreas in 1992. The game follows Carl 'CJ' Johnson's story of returning home after his mother's murder, rebuilding his gang, and uncovering the truth behind her death. The game is played from a third-person perspective with open-world exploration on foot or by vehicle. However, this evidence does not contain any information about GTA Online, its features, or how it differs from story mode. The provided text only covers the single-player narrative experience of San Andreas, not the multiplayer components that came later with GTA Online.