A group of cells with similar structure or function is called a tissue.

Here's a breakdown:

* Cells: The basic unit of life.

* Tissue: A collection of similar cells working together to perform a specific function.

* Organ: A structure composed of different tissues that work together for a common purpose.

* Organ System: A group of organs that work together to perform a complex function.

* Organism: A complete living being made up of multiple organ systems.

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