A group of cells that have the same function is called <u>a tissue</u><u>.
</u>A group of tissues that have the same function is called an organ. <u> </u>A group of organs that have the same functions is called an organ system <u> </u>(these are just in case you need them)<u>
A group of cells that have the same function is called a tissue.
Explanation:
A tissue consists of a group of cells that usually have a common origin, work together and are arranged neatly to carry out a specific function. The cells make up a certain structure and each of the cells that make up the structure (the tissue) are essential for it to do its own function.