What is the difference b/w an organ and organ system?-​

A group of tissues which have common origin and perform similar function make up an organ. Organ is the collection of tissues performing similar function. Organ is large and forms a part of the body. Organs together form organ systems.

An organ system is a group of organs that work together as a biological system to perform one or more functions. Each organ does a particular job in the body, and is made up of distinct tissues.

a symbiotic relationship with the mitochondria