Answer:
Organ - Structure composed of two or more cells
Explanation:
Organ is a group of tissue that is specified to perform similar function. In higher organisms organ combine to form organ system such as Liver.
Two or more cells that will perform similar function are combined to form a tissue not an organ. Tissue is an organizational levels that lies between cells and organs.
The organizational levels of human are cells, tissues, organs, organ systems, and the human organism.
