Here's a breakdown:

* Cells: The basic building blocks of life.

* Tissues: Groups of similar cells that work together to perform a specific function (e.g., muscle tissue, nervous tissue).

* Organs: Structures made up of different types of tissues that work together for a common purpose (e.g., heart, lungs, stomach).

* Organ Systems: Groups of organs that work together to perform a major bodily function (e.g., digestive system, respiratory system).

So, tissues come together to form organs, which in turn combine to create organ systems.