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 tissues that work together to perform a complex function (e.g., heart, lungs, stomach).

* Organ Systems: Groups of organs that work together to carry out major bodily functions (e.g., circulatory system, digestive system).

So, organs are the next level of organization after tissues, combining different types of tissues to create a more complex and specialized structure.