asteroids and meteroids are basically the same thing. meteroid are broken off debri from asteroids. while comets are completely different, instead of being rock and dust like asteroids and meteroids, they hace ice particles. comets also have tails which make them look and physically different
THe Saturn Rings are a "Belt" of asteroids that have all found a similar orbit around Saturn. They are made after a collection of asteroids fall into the same orbit, and when observed from a distance, look like the classic "rings".