Memory Levels of organization LTVersión en línea Find the pairs. por Laura Quiroga Sánchez Organ system: Group of one or more Organs working together to perform functions for the organism. Tissue: Made of several cells similar in structure and function that work together to perform a specific job. Organism: Entire living thing that carries out all basic life functions. Cell: Basic unit of structure and function in an organism. Organ: Made of similar tissues that work together to perform a specific activity or job.