A group of cells that all have the same basic structure and function come together to form a tissue.

Here's why:

* Cells: The basic building blocks of life.

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

* Organ: Made up of different tissues working together for a common purpose.

* Organ System: Multiple organs working together to carry out a major body function.

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

So, the progression from a single cell to a complex organism involves increasing levels of organization, with tissue being the first step beyond individual cells.